Durable Boating Accessory: Designed with 5/8 diameter x 5-1/4” roller shaft; made with hot-dipper galvanized panel bracket for added strength Roller/Bracket for Perfect Fit: Use with 4” roller and mount with 1/2” or 7/16” fasteners for optimal use Adjustable Bracket Slots: Mounting slots are on 2” centers and have 1/2” x 5” slots for adjustment to best fit the hull Easy to Use Boating Tool: Roller bracket comes pre-assembled for easy installation, saving you time and hassle CE Smith Marine Accessories: CE Smith is committed to providing quality trailer and fishing products with responsive customer service