slbrillreQuality materials: 4241 high speed steel, titanium coating to reduce friction when cutting, easy to cut iron 1-5mm, aluminum, wood, plastic, long service life. Proven performance and long service life when drilling holes Multiple sizes: Step drill with five different sizes to meet different drilling size requirements. Automatic cushioning: When the level is pressed against the surface of the object, a high impact force is automatically generated, and the adjustable cover can adjust the impact force. The surface is very non-slip and allows precise positioning without worrying about errors. Construction featuresslbrillre drill bit with double groove and smooth design, prevents cutting drops. Three side handles prevent slippage, and each step on the step drill is marked with the corresponding size indications. Easy to use The double-edged design allows for faster and smoother drilling, do not let you feel stagnation and resistance when using it. It has the best speed and accuracy. When working the step drill, pour some water, can effectively extend the service life. Sizes: No. 1: 6 levels from 3/16" to 1/2" 6 (3/16'', 1/4'', 5/16", 3/8'', 7/16'', 1/2'') No. 2: 13 levels from 1/8" to 1/2" (1/8", 5/32", 3/16'', 7/32", 1/4'', 9/32", 5/16", 11/32", 3/8'', 13/32", 7/16'', 15/32" , 1/2'') No. 3: 9 levels from 1/4" to 3/4'' 9 (1/4'', 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4") #4: 10 steps from 1/4" to 1-3/8"' 10 (1/4'', 3/8", 1/2", 5/8", 3/4", 7/8", 1", 1-1/8", 1-1/4", 1-3/8") #5: 12 steps from 3/16" to 7/8" 12 (1/4'', 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 13/16", 7/8") Package Contents: 1 x 1/4-1-3/8 Step Drill Bit. 1 x Step Drill Bit 3/16-7/8. 1 x 1/4-3/4 step drill bit. 1 x 1/8-1/2 step drill bit. 1 x 3/16-1/2 step drill bit. 1 x Automatic Center Punch 1 x Aluminum Box.