CM Special Theatrical Alloy Chain (STAC) is used for theatrical rigging applications where bridle adjustability is required. Made from heat treated alloy steel to provide long life, each link is proof tested to assure weld and material integrity. [break] The 4:1 design factor meets NACM GR80 standards for strength. Pieces are tagged with grade, reach, size and working load limit for positive easy identification. The link accepts shackles up to 3/4 inch for versatility and adjustability. [break] Pro audio rigging design, roof attachment, supplemental structure, sales, support and PE stamped drawings in any US State provided by Polar Focus. Call us today for more information at (413) 586-4444.