1/8 inch Drywall Cutting Bits - Pack of 10 - for Rotary Tools Each bit is 1/8" [3.2mm] shank thickness x 2-1/2" [6.35 cm] long Drill bits are designed to cut irregular cut outs on drywall (gypsum Board) Can also be used on thin plywood (less than 1/4" thickness) Fits all rotary tool brands