The Allen 20mm Double Allenite Through Deck High Load features a durable acetal body, perfectly shaped to house the sheave, allowing for smooth guidance of rope and wire control lines through a deck. This block is designed for adjustable rigging and other heavily loaded applications, and is available with one or two sheaves in both plain and ball-bearing systems. The plain bearing sheaves can withstand high loads without the risk of failure, while the stainless steel sheaves provide increased efficiency and durability for wire control. This product is ideal for leading rigging wire through any surface.