The thread specification range of rebar is generally 6-50mm. We usually involve more are 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 28mm, 32mm, 36mm, 40mm and so on. National allowable deviation :6-12mm deviation in ±7%, 14-20mm deviation in ±5%, 22-50mm deviation in ±4%. Generally, the fixed length of rebar is 9m and 12m, among which 9m long thread is mainly used for normal road construction and 12m long thread is mainly used for bridge construction.