A:AnswerBluetooth typically has a range of about 30' (when it's mostly in line of sight or slightly off from that). In a gym you might have difficulty if your phones in a locker which is in a shielded environment (the locker) and is in a different room or location (walls aren't very friendly to Bluetooth devices).
A:AnswerSweat proof I've wore mines in soaking rain and they still powered through when you get in cover wipe them off especially before charging just in case a bit of water gets in the charging port let them dry for an hour or 2 hope this helps
A:AnswerHi Tamer, we understand your concerns with the Headphones. Please fill out the form below and one of our social media specialists would be happy to assist you. http://smsn.us/SamsungSupportUSA and we will respond accordingly. ^Britt