Specifications: #4241 High Speed Steel is perfect for drilling holes in thin mild steel, aluminum, copper, brass, plexiglass, wood and laminates; Two flutes design for true round holes and automatically deburrs as you drill; Tri-flat shank design for sure grip in chuck without slippage; Set Includes: 1/4" Shank: 1/8" to 1/2" holes in 1/32" steps; 1/4" Shank: 3/16" to 1/2" holes in 1/16" steps; 3/8" Shank: 1/4" to 3/4" holes in 1/16" steps; 3/8" Shank: 3/16" to 7/8" holes in 1/16" steps; 3/8" Shank: 1/4" to 1-3/8" holes in 1/8" steps