100% brand new and high quality A tuned port designed for bass drum Extends low-end frequencies Adds more punch to your sound Makes the bass part more powerful; effect is adjustable by changing the tightness of the drum surface Instantly improves the sound of any bass drum Highly wear-resistant and durable Usage: First place the protective sticker on the drumhead and cut along the inner diameter circle to create a complete circle. Attach the rubber part of the enhancer to the drumhead – installation complete Color: Black Material: ABS + Rubber Size: Outer diameter: 18.5 cm Inner diameter: 10.6 cm (4.17 inches) Height: 10.5 cm (4.13 inches) Weight: 190 g (6.7 oz) Package Contents: 1 x Bass drum enhancer 1 x Protection sticker Only the above package content is included; other items are not included Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowance: +/- 1-3 cm