"The Big Boy 52"" Alumi-Loc attaching bracket secures hook-end loading ramps to pickup truck beds and trailers or any flat surface. Loading ramps with hook-ends fit into a specialized bracket channel, effectively securing the ramps in place without requiring tie-down straps to prevent ramp kick-outs during loading. ALUMI-LOC-52 is compatible with Big Boy II MF2, Whiteout Snowmobile Ramps, and heavy-duty MF2 Loading Ramp systems. Mounting hardware ALUMI-LOC-KIT is sold separately. all-aluminum construction. Made in the USA."