This professional ratcheting socket spanner set from YATO, consisting of 173 pieces, is particularly suited for use in the automotive and mechanical field. The sockets are made of durable chrome vanadium steel. They are equipped with the AS (anti-slip) drive system, thus increasing maximum torque by 25%. They also have a two-tone surface finish to protect the nuts. The sockets are made with a forging die, and then subjected to calibrations using precision gauges and control devices before being hardened. This tool kit is suitable for demanding, high-precision work.