How to use pin vise: Step 1: take out the suitable drill bit, and half unscrew the vise head.Step 2: half insert the drill bit, and screw the head tightly.Step 3: target the place where you are going to drill a hole, use one hand to fix the top of handle while using the other hand to rotate the handle.Size: 0.3-1.2mmThe shank diameter is approx. 3.175 mm, overall length is approx. 38 mm, which fit for processing PCB, normal FR-4, CEM-3 boards, , CNC, molds, plastic, circuit board, carbon fiber, composite board and so onSize: 3 Pieces of 0.5,0.6,0.7,0.8,0.9,1.0mm size, total 18 piece; 2 pieces of 1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9,2.0mm size, a total of 20 pieces; 1 piece of 2.1,2.2,2.3,2.4,2.5,2.6,2.7,2.8,2.9,3.0mm size, a total of 10 piecesMaterial: Metalcolour: black + silverPackage Contents:1 x Pin vise48 x Twist Drill bits10 x PCB Mini Drill Bits(0.1-1.0mm)Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.