Chains used for timber industry mainly include two kinds: one is tooth chain, the derivate of roller chain, which is similar to the roller chain adopting ANSI standards; it can mesh with standard chain wheels, and the sharp edge of the link plates will retain the timber during conveying; its maximal conveying speed can reach 380m/min; it mainly is used by the precision cutting equipment in the production line of wood processing. The other one is offset sidebar welded steel chain, including two narrow series, WH and WR, and two broad series, WDH and WDR. It's is designed for the preliminary processing environment of timber with sharp pounding, material abrasion and dust; it's is characterized by high load impact and its wear resistance.