Cup holder has a strong grip, primary material plastic with metal clamping structure. Can be attached to any table up to 1 1/2" thick. This works best on thicker surfaces. Area which touches surface is flat with padding to be gentle on the surface.
Ideas: attach to seat arm rest, swim deck, pontoon railing, or even your aqua water mat! Very mobile. Never "kick over" your drink again.
Thoughtful design has a small hole in the bottom is convenient for a charging cord to reach through or or easy drainage.