C.E. Smith Pontoon Square Rail Adjustable Clamp-On Rod Holder [55108A]Pontoon Square Rail Adjustable Clamp On Rod Holder All the same great features as the 304L stainless adustable clamp on (55105A) with a clamp made to fir the square rails found on pontoon boats. Each rod holder comes with 2 protective liners, one to fit 1" and one to fit 1 1 4" square rail. The liners are round on the outside allowing the rod holder to be adjusted to any angle above the water, and the hidden left or right adjustment allows even more