Description:1.Designed for use with rope or cord in indoor and outdoor applications, but only pulley here, rope is not included.2.A Crane Pulley Block is a kind of hoisting tool, also called a sheave, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present. Pulleys are used to change the direction of an applied force, transmit rotational motion, or realize a mechanical advantage in either a linear or rotational system of motion. Features:Main Material: Stainless SteelSheave Size: 15x10mm/0.59x0.39 inch(D*T) ;Overall Size: 58x21x33mm / 2.28"x0.83"x1.3"(L*W*H);Sheave U width: 7.5mm/0.29inch ; Package Content: 3pcs x Crane Pulley Block;