Seldén ratchet block (block with backstop for use primarily as a mainsheet foot block and for spinnaker and gennaker sheets driven "out of hand") with Delrin ball bearing and carbon fiber reinforced polyetherimide disc. The ratchet function can be turned on and off with the button on the side. pulley diameter: 60mm Working load: 250kg breaking load: 500kg max. line diameter: 10mm with 5mm shackle