Features 1、Made of ti-coated high-speed steel, these hex shank step drill sets have high hardness. 2、The step drill bit sets adopts groove design, help the electric drill clamp it more firmly, prevent sliding or falling off during rotation. 3、It is very suitable for using to cut holes in a variety of materials including steel, brass, wood, plastic, etc. 4、Cobalt coated for smoother cooler cutting, automatically deburrs holes as you drill. 5、Using high‑quality materials, strong and durable, has a long service life. Specification Features: - This Item ia brand new - This set replaces 50 individual drill bits. Two-flute layout gives you faster, smoother cutting. 3-sided (TRI-FLAT) shank will not slip in your drill's chuck. Cobalt coated for smoother cooler cutting - Ti coated to reduce friction and run cooler - Large bit has 3-sided shank and small bits have hex shank to prevent slip in drill chuck - Automatically deburrs holes as you drill - Long Life high speed steel - Includes protective padded aluminum case - Package Size:15cm*10.5cm*4.2cm(L*W*H) Sizes: #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 included: 1 x 1/4-1-3/8 Step Drill 1 x 3/16-7/8 Step Drill 1 x 1/4-3/4 Step Drill 1 x 1/8-1/2 Step Drill 1 x 3/16-1/2 Step Drill 1 x Aluminum Box Package List