Customer Ratings & Reviews

I was on a long back road the other day and saw a car with a flat tire pulled over to the side of the road and it was extra hot out too. It was at that moment I realized that I don't want something like that to happen to me so I better prepare so I can be safe than sorry. I browsed around for a tire inflator and saw this one and decided to get it since it not only would inflate tires but it also would serve as a jump starter as well. I have unpacked it, charged it and have tested it out so I know how to use it if I have to. I will say after using it and learning it ( which is easy to do ) I am very satisfied. I checked my tire PSI with my tire pressure gauge and it showed 31 PSI, I then plugged in this unit to inflate it up to its 33 PSI suggestion and it did it in no time. I then used my tire pressure gauge again and it was right at 33 PSI, so I know this unit did not over or under inflate it, it did just perfect. I also really like that it has included other tips to use as well so I can use it on other things like bike tires, basketballs, soccer balls, etc. Also it gives options on the unit itself to choose what you are inflating so it does it perfectly. The screen is large and easy to read, the buttons are easy to press and are separated enough so you don't press in on the wrong thing and it makes it simple. The built in flashlight is extra bright and even has a flashing option too, so if you should break down and it's not tires or battery you can use that so others will yield on the road. I also plugged in the jumper cables and I like that it is in my opinion dummy proof. The cable only plugs in one way as it's molded uniquely so I can't mix it up or plug it in backwards. I also like that the positive and negative jumper cables are different lengths as well, that way it stops it from the chance of them hitting each other and creating an accidental spark. The included USB cable did fine charging it as well. The included case it comes in is extra sturdy and holds everything in it a-ok, the one side even has a foam outline to keep it extra snug. I do have one recommendation though which I think is a great idea and that is to get a normal USB to lightning or longer USB to USB-C cable ( depending on what your phone or tablet uses ) to also put in the carrying pouch with the other stuff so if you do need to use it as a power bank for a phone or tablet, then the cable is always there ready to use. Overall though, I am very happy with it and in a strange way hope I never have to use it!

While on a trip to a trek in mountain I mistakenly left the lights on and my battery drained out when i got back. It was difficult to get a jump starter cable and to get another car to connect , to get the batter started again. It took 2 hours to find it in remote location. I have been using Rexing dashcam for long and have been happy with them and their quality is great. So when I saw a batter jump starter from Rexing immediately jumped on it. This is great tool to have it handy in car. Extremely simple to just connect, compact doesnt take much space and unlike manual it doesnt need long cables. This just works. Best part is it has air compressor as well. If your tire ever have a puncture you can temporarily fill it up drive to a safe location without damaging the rims, useful for emergency top off. Also with the other accessories can be used to top off soccer balls, bicycles when you take to a park. You can set the PSI and it shuts off automatically when preset level is reached. The torch light is also very bright functional and useful. And you can use it charge your phones through the usb port. Only Con I would say is the air compressor cable connection is little tedious , other than its a great multifunctional tool for car that is a must have.

Really impressed with this jump starter and tire inflator combo. Mine arrived fully charged and was ready to go right out of the box. It’s very easy to use, and the built in light is surprisingly bright, which is a nice feature to have if you ever need it at night or in a dark parking lot. I haven’t actually needed to use it to jump a vehicle yet, but honestly, that’s kind of the point for me. It gives me some peace of mind knowing I have a fully charged jump starter in the car if I ever need one. Having the tire inflator built in is another big plus since it means I don’t have to carry separate equipment. It’s compact enough to keep in the vehicle without taking up much space, and everything feels well thought out and convenient. Definitely one of those things you hope you never have to use, but you’ll be very glad you have it when the time comes.

I bought this device to keep in my wife's car in case of an emergency. It will inflate the tires or jump start the car in the event of a dead battery. I like the flashlight too and it's nice that it can be used to charge a phone if needed. It comes in a nice case with several accessories and it was fully charged when I received it. It allows me to worry less when I'm not with my wife and it will pay for itself if or when we ever need to use it. I'm glad to have this device.

I first experienced a Jumper Box when I last needed a jump, and the tow truck arrived with a little box instead of a set of jumper cables as I had expected. Well needless to say, I was blown away by the ease and convenience of it. Being a long time Rexing Dashcam customer, I was delighted to see that they branched out into a totally unexpected product line by coming out with their own dual purpose Jumper Box that has an integrated air compressor as well. Not only that, but it has a pretty bright emergency light and can also charge your phone. Hopefully I won't need it to jump my battery anytime soon, but I've already used it a few times to put air in my tires and pump up some pool toys. And of course I'll have it on hand if I come across anyone who may be in need of a jump. It's so much more convenient to use than having to line up a car close enough to use old style jumper cables. As usual, if it has the Rexing name on it, it's a quality product. Just remember to top up the charge on it every few months, so it's ready to go when needed. I deducted one star because I think it should be a bit more powerful, as in having a higher capacity battery to stay strong through repeated jumps if a car doesn't start on the first couple of tries as sometimes happens.

Great multi-function device in a handy take-along size. It even comes with its own custom durable carrying case with organizing pockets. The RJ21 is listed only as a 2 in 1 device but it can also be used as a 5v usb power bank, and it’s sized conveniently to take anywhere. I’ve found this and other Rexing products to be of high quality with lasting durability. The RJ21 is no different. Their customer service before and after the sale is reliable also.

This is a great portable piece of equipment that comes in a very compact and well designed case. Easy to use and comes in very handy for various tasks. Inflater for balls and tires work very quickly. The jump starter feature is so much better than finding jumper cables and getting another vehicle position for jump starting.

My Mazda3 randomly drains the battery sometimes and I've had to rely on a NOCO boost for a few years. While that product works well it's really junky packaging. It's got a little bag that doesn't fit all the parts to it so you end up having to force everything into the bag and it just flops around in the trunk and will end up open (because it's stuffed full) Huge pet peeve of mine. So when I got this one with the hard case, easy to fit parts. And the extra air pump (never had to use something like this, but might come in handy for a ball or something) it is an obvious buy over the other. Unfortunately in the weeks I've had this I haven't had to actually use the jump feature when I had a dead battery so this is all predicated on that primary function. I've never had a problem with rexing delivering on their core product promise so I'm not concerned with that. This being a strong competitor on price, with premium storage, more features, and a better charger (for mobile devices) makes this a clear choice over noco

I bought this mostly to keep in the car for those times when something inevitably goes wrong. I’ve had a portable jump starter before, but having the tire inflator built into the same thing is what sold me on this one. I tested the compressor on one of our cars when a tire was a little low and it worked great. It was nice not having to drive somewhere just to put air in the tire. The whole thing is pretty compact too, so it doesn’t take up much room in the trunk. I haven’t had to use it for a real emergency yet, which is probably a good thing, but I did test the jump starter and it worked without any problems. The flashlight is a nice extra to have as well. I also like that it can charge your phone if you need it. Hopefully I never actually need it on the side of the road, but I feel better knowing it’s there. For what it does, I think it’s a really handy thing to keep in the car and I’m glad I picked it up.

I'll be keeping this Rexing 2-in-1 in my trunk as it'll be a life safer if I ever need a jump. It jumped my sedan’s dead battery without any drama. The portable air compressor topped off a low tire in under three minutes flat. The built-in flashlight is bright enough for changing a tire after dark, which is important for an emergency flat situation. The USB port lets it double as a phone charger on long drives. The battery is smaller than some others, but that is exactly why the unit fits in a glovebox instead of eating up trunk space. It can hold several jumps before needing a recharge. The buttons are simple, the housing feels solid, and it does the two jobs I bought it for without fuss.

This device is a must have. I got one, and I used it to adjust the tires on one of the cars. It’s very easy to use, you just input the tire pressure level for the tires, connect it, and press the button. It stops inflating once the set level is achieved. The flash light also comes handy at night. I haven’t tried the jump start yet. The inflator can be used with balls, bike tires, etc. The size is great, it comes with a decent case, with accessories. It came almost fully charged. Overall, it’s great product.

This thing is awesome! I love that it has a jump starter and tire inflator all in one. Its compact enough to keep in the car and feels like a really solid product. The air compressor works great and is very handy when you need to put air in your tires. Having the jump starter gives me peace of mind, especially when traveling. The display is easy to read and everything is pretty simple to use. Really glad I bought this. For the price, having both features in one unit is a great deal. Highly recommend!

Really handy device to keep in the car - recommend one for all of my friends and family! The inflator is easy to use and topped off my tires pretty quickly, and I like that I don’t need to carry a separate jump pack and air compressor anymore. It feels solid and doesn’t take up much space in the trunk. Definitely gives me some extra peace of mind on longer drives, and when car-camping in remote areas where it's tough to find someone to give you a jump.

This is a very useful tool to keep in the car. Having both a jump starter and a tire inflator in one compact unit saves space - you are prepared for two of the most common roadside problems. I used the built-in air compressor to inflate all four tires on my car, and it worked great. It was easy to use, inflated the tires without any issues, and saved me a trip to the gas station.

I've been very happy with this unit. It does exactly what it's supposed to do and combines two important emergency tools in one compact package. The jump starter and tire inflator are both easy to use, and it's reassuring to have them available when traveling. It also comes with a nice storage bag that keeps everything organized and easy to store in the vehicle. Overall, a great value and a product I would recommend.

This jump starter is a great traveling companion at an excellent price. Its powerful jump-starting capability provides peace of mind, especially for larger engines. The built-in 150 PSI air compressor is incredibly convenient for quickly inflating tires without needing a separate device. This jump starter and air compressor combo does exactly what it needs to do. And it's just the right size to fit in the trunk.

Does exactly what it needs to without taking up half the trunk. Air compressor is fast enough for quick top-offs and the pressure gauge is accurate. Battery capacity isn't massive, so don't expect to jump big engines back-to-back, but it holds a charge sitting in the car and works when you actually need it. Definitely worth keeping around for peace of mind.

Originally bought this because I have been having problem with my wife leaving the lights on when parking. Showed her how to use the jump starter so no need for me to drive to help with jumper cables. She had no problem using this device. Looking forward to using the tire inflator to pump up some of my sport balls.

I'll admit that I was skeptical when I found this jump pack. I'm used to needing jumper cables or a jump pack the size of a small suitcase. This had no problem jumpstarting my fullsize SUV. The tire inflator is a nice addition as well. I was able to use that to fill up my kiddo's basketball with the included attachments.

Solid product without the huge cost of other brands. The tire inflator takes time but it's a small device so patience will give you the desired result. It also gets really hot but not alarmingly so. The battery charger is where it shines tho, as it will be able to give your battery enough juice to turn over when you let it charge for a bit. Great product!