I was surprised at how loud the beep was.  But no one else can seem to hear it when we're swimming.  There are 2 buttons, so not complicated at all.  A swim pal has one and warned that they break easily, BUT mine bounced on the locker room tile and still functions.  Hers is a couple of years old, so maybe the tech has advanced.  Mine is definitely helping me work on my timing.  It's also allowing me to work on my rotation, because I know when the next beep will come.

I really like  the tempo trainer.  It is helping me to slow down and concentrate on my stroke.  I also use it with my interval training.

easy to use and really helps me focus my training, would recommend to anyone

Love this in open water.  Helps even out my stroke.  Not so good in the pool as I get out of sync on the turns.  Easy to use and I share it with my friends.

I'm an older swimmer and I can't hear the beep.  I tried one before I bought one and I could hear that one. I returned the first unit I received because I thought the battery was failing!  Maybe they changed the frequency recently or maybe I have lost the ability to hear them between trial and purchase.

I am using this to train for more efficient and increased time in longer distance freestyle.  It has come highly recommended, and I fell optimistic about its training capacities.  I've placed it under my cap, w/o using the clip.  Glad to have made this purchase.