Description:1. Made of iron material, torsion resistance and pressure resistance resulting a longer service time.2. Designed with a screw compressor to adjust the flow amount of liquid in the hose.3. Strong clamping force, the experiment supplies held by the clamp will not fall.4. Widely applied for chemical testing, scientific experiments, teaching, etc.Specification:Material: IronOverall Size: 35x35mm / 1.38x1.38 Inch (L*W)Max Width of Adapted Hose: 18mm / 0.72 InchColor: Silver ToneWeight: 271gPackage Content:20 x Flow Control Clamps