Large Size Drink Holder - Big Water! Marine Grade Materials. Securely Holds Large Water Bottles. No drilling for installation. Our Flexible Gripping Clamp flexes open to wrap around the pipe and grips the pipe when the fastener is installed. During installation, adjust drink holder for desired angle and then tighten the 1/4" diameter Saltwater Marine Grade 316 Stainless Steel Fastener to secure it in place. Four clamp sizes available to fit most standard boat pipe sizes. Please specify pipe appropriate size when ordering. Contact us if you are not sure what size you require and we will send you a pipe measuring template.