The C.E. Smith Company Roller-Style Boat Guide-Ons 2-Pack are ideal for retrieving your boat on shallow ramps when you have no assistance or when there is a current or crosswind pushing the boat. The guide-ons roll smoothly, and the 21" galvanized posts extend up to 13" out from the edge of the trailer frame. C.E. Smith Company Roller-Style Boat Guide-Ons 2-Pack - Trailer Parts And Accessories at Academy Sports