Features:This set replaces 50 individual drill bits. Two-flute design gives you faster， smoother cutting. 3-sided (TRI-FLAT) shank will not slip in your drill's chuck. Cobalt coated for smoother cooler cutting.SELF STARTING - No need for a pilot hole.Cobalt coated to reduce friction and run coolerLarge bit has 3-sided shank and small bits have hex shank to prevent slip in drill chuckAutomatically deburrs holes as you drillLong Life True M2 high speed steelIncludes protective padded aluminum casePackage Size:15cm*10.5cm*4.2cm(L*W*H)Weight:450gSizes:#1: 3/16" to 1/2" 6 Steps (3/16''， 1/4''， 5/16"， 3/8''， 7/16''， 1/2'')#2: 1/8" to 1/2" 13 Steps (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'')#3: 1/4" to 3/4'' 9 Steps (1/4''， 5/16"， 3/8"， 7/16"， 1/2"， 9/16"， 5/8"， 11/16"， 3/4")#4: 1/4" to 1-3/8"' 10 Steps (1/4''， 3/8"， 1/2"， 5/8"， 3/4"， 7/8"， 1"， 1-1/8"， 1-1/4"， 1-3/8")#5: 3/16" to 7/8" 12 Steps (1/4''， 5/16"， 3/8"， 7/16"， 1/2"， 9/16"， 5/8"， 11/16"， 3/4"， 13/16"， 7/8")Package included1 x 1/4-1-3/8 Step Drill1 x 3/16-7/8 Step Drill1 x 1/4-3/4 Step Drill1 x 1/8-1/2 Step Drill1 x 3/16-1/2 Step Drill1 x Aluminum BoxDrill Shank Diameter1/4-1-3/8 9mm3/16-7/8 9mm1/4-3/4 9mm1/8-1/2 6mm3/16-1/2 6mm