1. 2. A tuned port designed for bass drum 3. Extend your low-end frequencies 4. Add more punch to your sound 5. Make the bass part more powerful, and the effect is adjustable; you only need to adjust the tightness of the drum surface Enhancer instantly improves the sound of any bass drum High wear-resistant and excellent durability Usage: 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 Color: White Material: ABS + Rubber Size: Outer diameter: 18.5 cm Inner diameter: 10.6 cm / 4.17 inch Height: 10.5 cm / 4.13 inch Weight: 190 g / 6.7 oz Package Contents: 1 x Bass drum enhancer 1 x Protection sticker Only the above package content, other items are not included Note: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. Measurement allowed error is +/- 1-3 cm