Adjustable Port Hole Rings For Bass Drums In Sizes 4", 5", And 6" Are Available Note:There is a little difference between the color and object. Features: 1. Durable silicone and stainless steel surround the port holes to strengthen them and avoid tearing the head,Implementing a simple microphone setup. 2. Available in three sizes 4inch/5inch/6inch to suit your application. 3. Bass Drum replicates the original Bass Drum snap-in design reinforcement system, adding durability and charm to transplanted bass drum heads. 4.Easy to install, just snap the O into the port hole to make your kick drum look complete. 5. The port grommet prevents the hole from spreading and also helps maintain the thick, rich thump from your bass drum. Package Content: Material: Silicone Metal Color: Black Brand name: Yibuy Size: Ring: 10/12.5/15 x0.5 cm / 4/5/6 x 0.25 inch(Dia x Thickness) Cutting part: 13.5x1.5x1cm/5.31x0.6x0.4inch(LxWxH) Weight: 130g Package include: 3 x Port Hole Rings 1 x Hole Cutting Each item is qualify checked with a unique Manufacturing Part Number label on the inner package,in order to confirm if it is authentic item sold by our store. Any question,please contact and send us the MPN label information. Durable silicone and stainless steel surround the port holes to strengthen them and avoid tearing the head,Implementing a simple microphone setup. Available in three sizes 4inch/5inch/6inch to suit your application Bass Drum replicates the original Bass Drum snap-in design reinforcement system, adding durability and charm to transplanted bass drum heads. Easy to install, just snap the O into the port hole to make your kick drum look complete. The port grommet prevents the hole from spreading and also helps maintain the thick, rich thump from your bass drum.