Feature:1. [Versatile Binding Machine] Customize paper margin with 3mm, 4mm, 5mm options for professional look. Accommodates letter size, A4, A5, or smaller sizes.2. [High Performance] This comb binding machine can punch up to 21 holes and 12 sheets of 80g paper at once. The maximum binding capacity is 450 sheets (80g).3. [Compact and Sturdy] The hole punch binder machine is lightweight and easy to carry in school or small office environments. Easy to move with one hand.4. [Humanized Handle] The book binding machine is designed with a humanized curved handle for effortless pressing, making the operation easier and more convenient.5. [Alloy Steel Blade] The blade of this book binder machine is made of alloy steel material, sturdy and sharply, offering clear and no burrs punching each time.Specification:Item Type: Binding MachineMaterial: Alloy SteelHole Size: Approx. 3x8mm / 0.12x0.31inHole Punching Quantity: 21 HoleMaximum Binding Capacity: 450 Pages (80g)Punching Capacity: 12 Pages (80g)Margin: Approx. 3mm / 0.12in, 4mm / 0.16in, 5mm / 0.20inHole Spacing: Approx. 14.3mm / 0.56inApplicable Paper Width: 300mm.Package List:1 x Binding Machine1 x Handle1 x Testing Paper1 x Instruction Manual