Well, this looks pretty. But I tucked it inside my shirt one day for a winter run (because I didn't have a lapel to clip it to), and apparently it got sweat inside the unit. Half of the display stopped working almost immediately, and shortly afterward, the interval alerts were intermittent at best. I missed the window to return it, so I tossed it and got one from Jeff Galloway's site - that one has been sweated and rained on and still works like a champ, even after I wear it inside my shirt.

This is my second Gymboss. I have one for my daily home yoga practice, and now also for the carry-out bag. Gymboss keeps my practice disciplined. I don't have to count or guess. My practice calls for 65-70 seconds on each side of each pose. The timer is set for 1 min. 30 sec. to give me enough time to get into the next pose of switch sides. Therefore, I can think about the poses, and I know I'm giving each side/each pose the same amount of time. I can't imagine doing my yoga without Gymboss.

I bought this timer for interval training. I like this timer but it's complicated to set up. It doesn't come with very helpful instructions, but you can find some good videos on YouTube. I've accidentally messed up the timer settings at the gym, and then I can't use it again until I watch a YouTube video again and set it back up.

Maybe as I use it more it'll become easier to use.

The stop watch and clock functions are straightforward. The interval settings, not so much.

Just an FYI, for intervals you can only set one value for work and one value for rest. So you can't have decreasing or increasing work or rest intervals. But I would not expect this type of functionality at this price point.

Second Gymboss. Loved the first one, but the display got wonky after several years, so I ordered this one to replace it.

THE POSITIVE - This is the most awesome little gadget if you're training for a long run. I really like the Jeff Galloway method of training, and this makes it so easy to do. I bought my first one years ago for my first (and only) marathon. The Gymboss performed superbly - wish I could say I did, too...but it's not nice to lie in a product review.

THE NEGATIVE - Unfortunatelly, the negative completely outweighs the positive. This Gymboss dies, consistently and predictably, about 20-25 minutes into a run. I've tried different kind of batteries, all brand new. Makes no difference. But here's the really goofy thing: If I take the battery out when this happens, and then replace it, the Gymboss pops back to life and lasts for two hours. This behavior has repeated 3x - it's not my old, tired imagination.

I'm really bummed. It's past the return date (of course) and I'm not going to buy another one. But it was great while it lasted. (NOTE: On their website, Gymboss warranties the device for one year, if it's defective. But here's the trick - if you bought it through Amazon, you have to return it through Amazon. And when you try, it says "Nope, sorry. Past the 30 day limit." Gee, that's helpful.)

***POSTSCRIPT - Superb service from this seller. Less than 12 hours after inquiring, a new Gymboss is on the way. Impressive!
*** 2nd POSTSCRIPT - So far, the new Gymboss works flawlessly. Training for a half using Jeff Galloway method. The Gymboss is indispensable. ( I lost the cover that goes over the battery, so a little duct tape did the trick. And then customer service sent me a new cover)
*** And yet another follow up. Just about four weeks in with the new one, and found out Gymboss is not sweat-proof!! One long run on a hot day and the screen clouded over, the buzzer stayed on continuously. Removed the battery to silence it - did the rice thing for 24 hours. It's working again, but come on. This should not be necessary..

Glad I waited to review this product. I loved this timer at first. Now that the beeper no longer works, it's a pain in the butt. I now have to place the timer on a floor or desk to hear it vibrate while I work out because the beeper is broken. It's still a good concept for people like me who don't want to watch the clock while doing interval training but I'm bummed that it's broken already.