Single Ratchet BlockSchaefer M66-08 Single Ratchet Block. Injection molded long grain fiber body features an anodized aluminum sheave for a light yet strong block. Delrin(tm) ball bearings ensure smooth operation. Machined aluminum sheave features ten facets for secure line control. Swivel head may be locked in place. On/off switch is located on both sides of the block for easy operation. Specifications:Length 5.25" (133.35mm)Width 2.59" (66mm)Thickness 1.13" (28.7mm)Sheave Diameter 2.59" (66mm)Maximum line 1/2" (12 mm)Weight 6.8 oz (192 grams)Shackle pin .25"Safe working load 750 lbs (340 kg)