Labor Saving Wrench adopts high efficiency planetary shifting as main drive. It futures small dimension, lightness, durability and large gear ratio and thas a large out put tarque can be priduced by inputing less force. The product is made of high grade alloy steel in the process of fine heat treatment . The outer surface is polished with the plastic spray treatment and has a fine feel. The wrench is widely used to assemble and disassemble the tyres of various heavy trucks. It is a necessity for repairmen or drivers.