This is a brilliant little tracker. I bought it as a cheap tracker to keep me going between the time I lost my flex and the new fitbit charge HR came out. I'm using the charge hr now but the other half has inherited the zip and loves it too. I think I preferred it to the flex as the fact that you never have to charge it is a great advantage. Also, it's more discreet to hide etc and harder to lose than the flex with its dodgy wrist strap. It's excellent value for money too and I think if the fit bit charge hr hadn't come out, i'd be wearing the zip for a long time to come - the lack of need to charge far out-weighing not being able to bring it into the shower etc. The display is a bit hard to see but i had it hidden away anyway so I used my phone if I wanted to check my stats. The app is excellent. Would recommend.