4PCS 4-6inches Woofer Speaker Ports Vent Connectors Inverter Tubes Kit with 45mm Hole45mm Hole

Feature: 1. The speaker phase-inverting hole, also called sound tube or air hole, is often used in the inverted-phase speaker. 2. It adopts ABS plastic material, sturdy and durable, suitable for 4-6 inch speaker. 3. Smooth inner wall, with both ends designed as horn mouth. Smooth airflow, obviously reducing the sound. 4. Long service life, not easy to damage, and you can use for a long time. 5. It is mainly to pour the sound pressure of the airflow vibrating inside to the front, and overlap with the sound pressure radiated from the speaker to make a bass effect. Specification: @font-face{ font-family:"Times New Roman"; } @font-face{ font-family:"宋体"; } @font-face{ font-family:"Calibri"; } @font-face{ font-family:"Arial"; } @font-face{ font-family:"Tahoma"; } p.MsoNormal{ mso-style-name:正文; mso-style-parent:""; margin:0pt; margin-bottom:.0001pt; mso-pagination:none; text-align:justify; text-justify:inter-ideograph; font-family:Calibri; mso-fareast-font-family:宋体; mso-bidi-font-family:"Times New Roman"; font-size:10.5000pt; mso-font-kerning:1.0000pt; } span.msoIns{ mso-style-name:""; text-decoration:underline; text-underline:single; color:blue; } span.msoDel{ mso-style-name:""; text-decoration:line-through; color:red; } @page{mso-page-border-surround-header:no; mso-page-border-surround-footer:no;}@page Section0{ } div.Section0{page:Section0;}Item Type: Inverter TubeTotal Length: Approx. 117mm4.6in (as shown)Hole Diameter of the Speaker Shell: Approx. 45mm1.8in (as shown)Material: ABS plastic Compatibility: 4-6inches speaker Package List: 4 x Inverter Tubes