Precision Marine Hardware Rail Mount Rod Holders are constructed of Stainless Steel and high impact plastic. These Rail Mount rod holders will fit stainless steel railings from 7/8" to 1 1/2" round or square tubing. They can be mounted either on a vertical rail, horizontal rail or a rail on just about any angle. The angle of the tube is fully 360 degrees adjustable. The rod holder is secured to the rail with 4 stainless steel bolts, no drilling of the rail is required.