Features: Compared with a speaker without an inverter tube, this structure can significantly enhance the low-frequency radiation intensity, increase the volume, and improve the efficiency of the speaker.. It can increase the volume of the without increasing the power of the speaker itself.. Standard mount holes make this tube easier and convenient to install than others on the market. These port tubes can overcome the poor sound quality and you can experience good looks, low distortion, and superior overall sound quality.. brand new and high quality Speaker Port Tube is used to improve the response of many types of speakers. Specifications: Item: Speaker Port Tube Material: Plastic Color: Black Quantity:2PCS Size::approx 160x111mm/ 6.3x4.37in Inner Diameter:99mm/3.9in Package Includes: 2 PCS x Speaker Port Tubes (Without Speaker) note: Please check the mountingn size clearly before buying the item. Due to the lighting effects and shooting angles, there is color difference in the product, please understand. Due to manual measurement, there is a tolerance in the product size.