Satin finished carbon steel body with 1/2"Sq drive for use with ratchet wrenches. May also be used with a 20mm spanner. Heavy-duty chain. Satin finished carbon steel body with 1/2"Sq drive for use with ratchet wrench. May also be used with a 20mm spanner. Heavy-duty chain. Drive: 1/2"Sq. Model No. AK641 .