Harken 57mm T2™ Loop Soft-Attach Block 2151The high strength composite T2 is the first block with no metal shackles or rivets. It is used for traveler controls, mainsheets and vangs, cascades, bridles, and other systems where small, lightweight blocks are called for. The T2 Loops on off loop system slides through the block head and over the anchor post for a secure connection. A SK75 Dyneema loop is included. Replacement loops available. Part No. 2151 Sheave (mm) 57 mm Sheave (in) 2 1 4 in