The 20mm Double Allenite Through Deck is designed to provide smooth and efficient guidance for control lines passing through a deck. Its durable acetal body and perfectly shaped sheave ensure reliable performance for adjustable rigging and other high-load applications. Choose from single or double sheaves and plain or ball-bearing systems to fit various needs. The patented stainless-steel bearing system with twin rows of bearings on a stainless-steel rail offers superior load-carrying capacity and longevity compared to plastic rail systems.