This silencer muffler insert is made of iron material, which is of high hardness. So it is very durable. It can effectively reduce noise, on the other hand, it can also reduce noise contamination, which is environmental friendly. These items fit for the tail exhaust pipe diameter size of 35mm / 42mm / 45mm, and there are three diameter measures for you to choose. You can choose the proper one. Don't hesitate, such an environmental friendly and convenient product, you shouldn't miss it. Features: 1. Universal removable muffler silencer. 2. Can effectively reduce deep note sound, also reduce noise contamination. 3. Metal construction, very durable. 4. Easy installation, adjustable and removable. 5. Fit for the tail exhaust pipe diameter size of 35mm / 42mm / 45mm. Specifications: Color: Silver Material: Metal Package Weight: Approx. 112g Optional Base Diameter (millimeter): 35mm / 42mm / 45mm Optional Diameter (inch): 1.38" / 1.65" / 1.77" Whole Length: Approx. 135mm / 5.31" Thread Size: Approx. 6mm / 0.24" Package Included: 1 x Silencer Note: 1. Please allow 1-3mm error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard. 3. No instructions included. Professional installation is highly recommended. 4. Please check the size measurement chart carefully before making payment. .