64mm x 115mm Speaker Port Tube Subwoofer Bass Reflex Tube Bass Woofer Box 1pcs Sharpening Stones it make the board sturdy

it make the board sturdy enough to keep level and stable

All-copper DB37 Plug

67-inch (L*W*H) (Retracted)

Pull Out Length: 316mm / 14

64mm x 115mm Speaker Port Tube Subwoofer Bass Reflex Tube Bass Woofer Box 1pcs Sharpening Stones it make the board sturdyFeatures: Speaker Port Tube is used to improve the bass response of many types of speakers. There are plenty of types to help you with your vented box design, and carries tubes of every shape and size, including adjustable length ports and flared ports. These port tubes are a reliable, convenient installation, while at the same time providing a finished, "pro" look to your bass reflex speaker building project. Normal tubes suffer from nasty turbulence