... WOOD PLUGS PRODUCTION ON HIGH EFFICIENCY High quality plug cutter for wood in different types on high ... working efficiency.Diameter for plug(metric):6,8,9,10,12,14,15,16 ... ,20mmDiameter for plug(inch): 1/4", 5/16", 3/8", 7/ ... 1/4" Hex Quick Change System or 8mm diameter round straight shankSurface treatment: Bright finished or Black-oxidedHardness: HRC44 ...