1. Secure Installation for Diverse Boats: This galvanized swivel top bunk bracket kit is designed for installation on boat trailer crossmembers, securely fastening your bunk boards to the swiveling tops. The adjustable swivel top support pads allow precise angle alignment to match your boat's hull contour, whether angled or flat. 2. Extended Thread Design for Versatile Compatibility: Features a 3.1-inch extended thread design suitable for 3"x3", 2"x3", and 1.5"x3" trailer crossbeams. The boat trailer bunk brackets kit includes U-bolts (1/2" diameter, 3" width, 4.5" length) for secure mounting on various crossbeam sizes. 3. Heavy-Duty Construction for Durability: The bunk brackets for boat trailer constructed from heavy-duty metal with a galvanized surface, providing superior rust and corrosion resistance. The robust design ensures longevity and prevents bending or deformation in marine environments. 4. Adjustable and Easy-to-Install Design: Industry-standard 8-inch height with slotted holes for multiple height adjustments. The brackets can be easily fixed on boats and trailers, ensuring a secure fit for ski boats, fishing boats, or sailboats. 5. Complete Package for Easy Setup: Includes 4 rectangular brackets, 4 trapezoid brackets, 4 U-bolts, and all necessary installation hardware. NOORSUMD 4 Pack 8" Galvanized Swivel Top Bunk Brackets for Boat Trailer with Hardware Kit, Compatible with 1.5"x3", 2"x3", 3"x3" Crossmember