Common aliases: chain hoist, chain block. Core driving mechanism: Manual operation of a reciprocating handle, which drives the chain through a gear system. Main functions: Lifting, towing, and tensioning; some models can be used horizontally or at an angle. Typical rated loads range from 0.25 tons to 9 tons. Key features: Compact design, easy to carry, does not require a power source, and is simple to operate.