Stand-up bases allow a wide variety of blocks to be held upright, swivel freely, or pivot so lines have a fairlead under load. The ball-and-socket design lets blocks articulate up to 45 degrees and swivel freely. The 460 and 461 bases (high-load versions of the 010 and 029) have stainless steel reinforcement plates to handle the high load capacities of 57 mm and 75 mm Carbo blocks. 461