The Antal 9040 Snatch Block Diameter 40 X 12 HRm - is equipped with a revolving cheek plate that allows the block to open around the sheave axle. A safety ball feature, with an adjustable screw to lock it in place, prevents the block from unintentionally opening. The block also includes a becket for the hanging line, and can be attached using a highly resistant spectra line. Its sheave has a composite fiber main bearing and double side ball bearing, surrounded by hard anodized and teflon coated aluminum cheek plates with side rubber protections. Here are the specifications: 40 mm (1 9/16") snatch block has a safe working load of 1543 lb (700 kg) and can accommodate a maximum line size of 1/2" (12 mm). The 60 mm (2 3/8") snatch block has a safe working load of 2866 lb (1300 kg) and can accommodate a maximum line size