This is without a doubt the best drink holder we have ever seen. It folds flat when not needed, flips down for use. It has adjustable drink holders to accommodate everything from small cans to 32 oz. bottles.
The mounting system fits 0.75 to 1 in (2 to 2.5 cm) round tubes, plus adjusts for different angles on the tube. Size: 3.75 in width x 4 in in height (9.5 X 10 cm).