Tempo Trainer does what it says it will do. Plenty comfortable under your cap, and yes it does float.

Unfortunately, this product hasn''t worked for me. The literature  advises using with a swim cap, but swim caps are very uncomfortable.  I developed a headband to hold the temp pro directly over my ear only to find that I could not hear the tempo tone under water.  

This product needs a volume control as well as a successful way to mount the temp pro without having to use a swim cap.  Unless or until these improvements are made this product is a total waste of money.

I have used the TT Pro about 20 times now.  It works as advertised.  I haven''t tried all the different functions.  I pretty much just use it to set a tempo to swim to.  It is much easier to use that my previous TT.  The buttons make it easier to adjust the timing.

ok this thing really works and is easy to use. the floating feature is handy since it fell out of swm cap the second time I was using it (my fualt). Also helps with pace. I thought I was swimming a consistent pace until I got this thing, now swimming better pace. The beep keeps you from being lazy and makes you swim strong.

this is really helping me keep a better pace

I am enjoying this device for my training to maintain and adjust stroke rate.  I''ve not had it long enough to rate longevity.  It does what is advertised.  The buttons are a bit difficult to use when the device is placed under a swim cap.