It's a cool device to check out.. All you gotta do is plug it in, place the mouthpiece on the end.. Have your client (or yourself) clamp your nostrils with the included noseclip.. You have to breathe into the Bodygem itself for 5-10mins.. It beeps a couple times to start, then the motor kicks in, that's when you breathe into it like normal thru your mouth.. After the time's up, a long beep indicates it's done, and the screen displays your BMR.. Last I tested, it said 3560.. My first time was 3240.. Been awhile since I've used it.. Remember to not eat at least an hour prior testing.. :thumbsup: