Review on OSPORT Lightweight Full Carbon Fiber Bicycle Water Bottle Cage Holder, 18g - 1 Piece by Tim Harrington

Two of these were installed behind my saddle and my water bottles disappeared at the end of my driveway. I thought maybe the hit was too big, but then I lost both bottles again and just made a smooth turn at high speed. The TT bike only has cage mounts on the down tube so I slipped one in there and all is good. I even did some test runs over big bumps and was hesitant to fit it to a seat tube mount for fear of losing the bottle. I would categorically NOT try them on MTB. According to my scale, they weighed about 15.5 grams. (without screws). I can't use them for their intended purpose but for the price I'll throw them on my commuter road bike and keep them.