Features : *Made of high quality material, durable and practical to use *This compact set replaces 28 individual drill bits *Two-flute design for faster, smoother cutting *Including one 3/16-inch to 1/2-inch six-step bit,One 1/4-inch to 3/4-inch nine-step bit, one 1/8-inch to 1/2-inch thirteen-step bit,titanium coated *Suitable for workpieces with hardness below 25, such as iron plate, steel plate, PV plate, and insulation plate. *Use tools: both pistol drill and bench drill *Note: Water cooling while working can effectively extend the service life of the drill bit. The recommended drilling speed is 250-400 rpm Specifications : *Material: 4241 High speed steel *Color: gold(As pictures show) *Step drill bit size: 3/16-1/2 ,Six step bit: 3/16", 1/4", 5/16", 3/8", 7/16", 1/2"; 1/4-3/4 ,Nine step bit: 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4"; 1/8-1/2,Thirteen step bit: 1/8", 5/32", 3/16", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 13/32", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 13/32", 7/16", 15/32", 1/2" *Quantity:3pcs Package Contents: 3pcs Step Drill Bit Note : 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 2. Please allow slight manual measurement deviation for the data.