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™ universal head can be fixed in either of two planes, or free to swivel as required . Exceptionally high working loads Low maintenance, long service life Self-lubricating sheave Captive Lock™ universal head Slotted pin shackle eliminates fouled lines