High quality material: 3 PCS, 45 Steel Hex Connecting Rod + 4 PCS Adapter Head CRV chrome vanadium steel alloy, chrome plated, anti-rust, high hardness, wear resistant, sturdy and durable. Wide application: 1/4 hex conection rod transforms square head (1/4inch3/8inch1/2inch), inside to outside square extension head (1/4inch -; 3/8 inch, 3/8inch -;1/4inch, 3/8inch -; 1/2inch, 1/2inch -; 3/8inch), suitable for electric drill, pneumatic drill, electric wrench, manual wrench, pneumatic screwdriver, electric screwdriver etc. Colorful color mark: The colored joint connection rod, 1/4inch square head ( length: 65mm ), 3/8inch ( length: 65mm ), 1/2inch ( length: 72mm ).The color corresponding to each model is random. Anti-breaking design of the steel ball: Steel ball makes connection tig and adapter head not fall off easily when using, safe and weak, compact connection can reduce screw wear. Passivation design: The two ends of passivation achieve install quickly, also easy to disassemble. Quantity delivered: 1 game