CE Smith Roller Style Boat Trailer Guide-Ons Makes boat loading easier with the CE Smith Roller-Style Trailer Guide-Ons. These smooth rolling guides assist in centering the boat onto the trailer. This style of guide-on is ideal for retrieving your boat on shallow ramps where the trailer is not far into the water or when you are trying to retrieve your boat alone. The uprights with rollers come fully assembled and ready for installation. Features 1-12 Pre-galvanized steel uprights lean outward 15