Review on Delta Cycle Expanding Beverage Holder: Ultimate Bike Cup Holder for Water Bottles, Coffee Cups, and More - Enhanced Grip and Easy Installation - Durable Construction by Peter Sullivan

I ended up sending it back. The mounting clip was too small to fit on my retro Schwinn 3-Speed (cruising style) which was the ultimate reason for returning it, but even if it wasn't I probably wouldn't have kept it. The plastic holder is curved inwards, which creates a very good fit. I'm sure it would keep the drink in place but it was difficult to get the cups out and would definitely get in the way when removing the cup while cycling. Also, the small pieces of rubber that increase grip kept falling off.