The Gymboss is the best timer I ever had. Even when I hate it and swear it is cheating me as it beeps my 10-second rest is up, and also am pretty sure that it is malfunctioning when it's not beeping that 60 seconds of burpees are finished despite my certainty it that at least 75 seconds have elapsed...it's the best timer I ever had. If you're a practitioner of HIIT, CrossFit, MMA, Tabata, or kettlebells, it could be your best worst buddy too.
The difference between the Gymboss and any other fitness timer or stopwatch is that it combines the lightness and portability of the former with the interval tracking capabilities and sound effects of boxing gym round trackers. The Gymboss can store and count 1 or 2 intervals of between 2 seconds and 99 minutes, and repeat them up to 99 times. In other words, if you're doing a cardio session that consists of 30 seconds of sprinting and 1 minute of walking, you can set the Gymboss for :30/:60, and it will beep first after 30 seconds and then again after 60 seconds for however many rounds you tell it to repeat the combo. It's an efficient and hassle-free way to keep yourself honest about work and recovery times.
Gymboss also functions as a straight stopwatch and clock, and has both beep and vibrating alarm settings. Alarm durations are also user-set to 1, 5, or 10 seconds. Water- and shock-resistant it comes in about a dozen different colors for both traditional and fancy girls and boys. Measurements are 1-3/4" x 2-1/4" x 1/2".
The Gymboss interval timer is a top Dude Gift for an Athlete pick.