Multi size include: 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm. Use with a cutting mat for long lasting blades. This item is a hole punch, it is great for sewing leather craft, paper, cutting rubber, plastic, etc. Instruction: Step 1: Firstly take down the screw in the top of the item, then put the right size of the punch blade, take back the screw and keep it tight enough to fixed the punch blade. Step 2: Fasten the leather/paper or something else, keep the punch vertical to the leather, then use appropriate energy to press the wood handle can punch the hole perfectly.