Manufacturer Part Number: PSP2-BKNT The unique flared-end construction of the Precision Port™ system enables it to outperform any standard port tube on the market. Proudly made in the U.S.A. Key Features: Reduces air turbulence to minimize or eliminate port noise Just cut to length glue together and install Gives your enclosures a sleek professional look Mounts in 4-1/4 diameter cutout Precision Port 2 Flared Speaker Cabinet Port Tube Kit The unique flared-end construction of the Precision Port™ system enables it to outperform any standard port tube on the market. Conventional tubes suffer from nasty turbulence at the entrance and exit of the port producing unwanted noise and poor sound quality. The Precision Port™ system overcomes these problems and as a result can actually produce a gain of up to 3 dB in output! Now you can experience good looks low distortion and superior overall sound quality thanks to the Precision Port™ system. The 2 model now comes with starter holes on the rear of the mounting flange allowing the user to decide whether to use 3 mounting holes 4 mounting holes or none at all! All you need is a standard twist-drill to make your custom mounting decision. The central tube can be cut to any desired length with a maximum overall port length of 11 . Once the pieces are cut the system can be permanently bonded with ABS pipe cement. Dimensions: 5-1/4 outside flare outer diameter 4-1/4 cutout 4-3/16 inside flare outer diameter. Also available in 3 4 and 6 diameters. Proudly made in the USA! To calculate the proper port length for your cabinet and tuning frequency use Precision Sound Products . Product Details BrandPrecision SoundModelPSP2-BKNTPart Number268-348UPC844632046773Unit of MeasureEachWeight0.75