Ronstan Series 50 All Purpose Single Block with universal head. 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. Use for Mainsheet and halyard applications, vang and spinnaker control lines on boats to 10m. Exceptionally high working loads. Low maintenance, long service life. Self-lubricating Acetal polymer sheave ensures low friction and extreme durability. Slotted pin shackle eliminates fouled lines. Made from Marine Grade 316 stainless steel load strap and head fitting and impact and UV resistant, fibre reinforced nylon cheeks. Dimensions: Sheave ? 50mm Rope ? 8mm -12 mm Max. Pin ? 5.0mm