Plastic and aluminum alloy material, sturdy and durable. Size 4 inch, clamping force is 30kg, maximum clamping distance can reach 3cm-10cm, total 4pcs for professional needs. Quick Clamp Fastening Tool This F clamp set can fasten workpieces quickly and precisely to make woodworking easier and more convenient. Easy to use trigger design allows easy one-handed operation and sliding arm and holds wood in place. Widely used in furniture manufacturing and packaging industries. Applicable. Suitable for spreading or clamping parts for welding, gluing or woodworking projects. Is the ideal toolbox accessory for DIY and woodworking, metalworking, modeling, etc. Note: The data is all manual measurement, please allow 1-3cm error. Due to the difference in light and display, there will be a certain color difference, subject to the physical object received. Delivery quantity: (according to the main picture)