I bought this watch few days ago, had same question but now I do have an answer. The watch that is non cellular and only has GPS has 8 gig internal memory. I have 215 songs and now I only have 2.2 gig left. So It won't hold 40,000 songs; but I am loving it because I can leave my phone in the car locked and hit the gym. To me it has full function of ipod with some adds on feature. To play the music you must have Bluetooth headphone paired, it doesn't work on speaker.