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. Becket pin is removeable so line can be spliced prior to fitting and is ingeniously locked into position without the use of a clevis pin, split ring or tool