Series 40 All Purpose Block - Single - Stand Up. All purpose (AP) blocks are a great all around solution. Self-lubricating Acetal polymer sheaves running on polished stainless steel races perform equally well with dynamic loads and high static loads. For durability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing. Captive Lock#153 universal head can be fixed in either of two planes, or free to swivel as required., Features: Exceptionally high working loads, Low maintenance, long service life, Self-lubricating sheave, Captive Lock#153 universal head, Mount with 2 x 5mm (3/16") fasteners (not supplied) , Applications: Mainsheet, Halyard, Vang, Spinnaker control lines on off-the-beach catamarans, one design classes and sportsboats up to 8M(26') , Materials: U.V. stabilized Acetal sheaves, Impact and U.V. resistant, fiber reinforced Nylon cheeks, Grade 316 stainless steel bearing race, Grade 316 stainless steel load strap and head fitting , Specifications: Sheave :