Block and Tackle with Cat. No. 268 Block Klein Tools 1802-30S Light, galvanized-steel shell blocks are fitted with snubbing hooks to hold the load Sheaves are strong yet lightweight aluminum alloy with all-bronze bushings Maximum safe load is 750-pounds (340 kg) These are not occupational protective hooks, not for human support Klein Tools doesn't just make great products, we make great products that stand up to the demands of the professionals who use them every day ... Since 1857.