The Allen 20mm Dynamic Block with Cheek is designed with a patented bearing system, using twin rows of stainless-steel ball bearings on a stainless-steel rail for superior load-carrying ability and longevity. It can be mounted to our Profix cheek adapter, allowing for articulation and proper alignment with the rope. This block is perfect for leading lines along a deck, into a cleat, or around corners, and is securely held in place by a single screw through the Profix cheek adaptor. For applications that require constant sheave movement, the Dynamic range is the ideal choice.