Crosby® McKissick 4-1/2" Tailboard w/ Bronze Bushings: 3/8"-1/2" wireCrosby McKissick 4. 5" Tailboard Block 3 8" to 1 2" Wire Rope The Crosby McKissick 4 1 2" Tailboard Block is built for efficient rigging and load control. Designed to work with 3 8" to 1 2" wire rope, this block features a 4. 5" sheave and durable bronze bushings for smooth operation under load. Rated for a 4 ton working load limit and meeting ASME B30. 26 standards, its a trusted solution for fixed point rigging in demanding environments. This Type