Features: By accurately calculating the pipe diameter and length, it can effectively guide the airflows inside and outside box, improving low-frequency efficiency. Quality ABS engineering plastic, sturdy and durability, not easily deformed or cracked. The inner wall of the pipe is treated with special technology, which is smooth and flat, and can greatly reduce friction sound without noise interferences. Two standard pipe diameters and lengths are available, suitable for most loudspeaker production and HiFi modification. Whether it's an inverted loudspeaker, subwoofer, or various instrument speakers, they can all be perfectly adapted. Essential accessory for sound enthusiasts, players, and maintenance technicians. Specifications: Component: ABS Plastic Size: large, small Dimension: refer to pictures Shape: L-shaped Package Includes: 1 Piece L-type Loudspeaker Phase Tube note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.