Perezy Enhancer instantly improves the sound of any bass drum. High Wear-resistant and excellent durability Using Method:First put the protective sticker on the kick drum skin,and cut along the inner diameter circle to make a complete circle.The rubber part of the loudspeaker is stuck on the drum skin and the installation is complete Colour:black Material:ABS+Rubber Size: Outer diameter: 18.5cm inner diameter: 10.6cm/4.17 inch height: 10.5cm/4.13 inch Weight:190g/6.7oz Package Contents: 1 x Bass drum enhancer 1 x sticker Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.