Review on WOHOOH Bike Seat: Waterproof Comfort for Men and Women with Taillight - Universal Fit, Shock Absorbing, Memory Foam Gel Cushion with Mounting Wrench & Allen Key by Cameron Aleman

This is a very handy product, it comes pre configured so it can be installed multiple ways and I was able to install it on my Trek. I really think the light is an absolute plus considering other locations. The flashlight is rechargeable and can flash in different ways when you are out at night. You'll have to work on the correct angle of the seat when mounting it on the mountain bike, as you are not mounting it at the top of the rack like on many bikes I wanted.