These blocks burst on the scene a few years ago. At the time they were the only adjustable auto-ratchet block. You can twist the shackle pin to tell the block at what load to engage. This allows the block to react to the load on your hand not on the sheave. We used these on a Lightning all last year and they worked great, we have also sold them for use on Laser mainsheet blocks, Opti's and J24 spinnaker blocks.

pin diameter: 5/32"

MWL: 550 lb

BL: 1100

Price: $71.90