Ginsco 3 Pcs 1/4" 3/8" 1/2" Extension Drill Bit Bar Hex Socket Power Driver Shank Adapter Power extension bit sizes: 1/4", 3/8", 1/2" Suitable for Quick Change 1/4" Chuck Systems or Directly into Drill Chuck Spring Loaded Ball Bearing on Head Holds Sockets Securely Change Your Hand Socket Set Into A Driven Socket Set Indentation for quick coupling with your impact drill or bit holder