The silver SwirlyGig Drink Holder by SwirlyGig is intended for use on 0.5" diameter tubing. It holds most common beverage containers including cans, glasses, water and beer bottles. It also holds other items like remote controls, phones, capos, reeds, pencils and picks. The inside of the basket is 3.12 x 4". It is simple to use and has no moving parts, with nothing to adjust or wear out. It fits snuggly in place, using only friction and gravity. It's made of resilient spring steel, then coated in protective PVC for grip and durability. It works great on lawn chairs, ice houses, crutches, lamps or any vertical 0.5" tubing.