Manual chain blocks if are overloaded, there is no danger of fracture. They will open slowly. The inside of the bottom hook, with ISO dimensions designed to be large and easy to stabilize the load. Hand manual chain hoist the ball and roller bearings mechanism Increases Mechanical Efficiency. The Load Chain Guide Mechanism facilitates the smooth movement of the load chain. Options, Overload protection device, Corrosion resistant chain. Hand chain hoist is a kind of widely used and portable manual operating hoisting machine,especially widely used on no power and liquied homework. Hand chain hoist maintenance, Hoists can be quickly disassembled for fast and easy maintenance Regarding Manual chain hoist details, Chain pulley blocks instruction,Manual chain blocks pictures, manual chain hoist price list, hand chain blocks features please kindly feel free contact with us. Professionally service hope will get your satisfaction. Shan Dong Finer Lifting Tools co.,LTD Skype: faithjiang888 Email: [email protected] Website: http://www.cargotrolley.com/