Series 50 All Purpose Block - Triple. Features: Exceptionally high working loads, low maintenance and long service life. Self-lubricating acetal polymer sheave ensures low friction and extreme durability. Slotted pin shackle eliminates fouled lines. Lockable swiveling head post. Snap fit removable becket pin. 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. Head can be locked at 0° or 90° by engaging the grub screw in either the 0 or 90 degree position. Applications: Mainsheet and halyard applications, vang and spinnaker control lines on boats to 10m (33ft) S60 - on boats up to 12m (40ft). Materials: Grade 316 stainless steel load strap. Impact and UV resistant, fiber reinforced Nylon cheeks. (Additional marketplace content: Great Product.)