Features: 43mm length tube is suitable for 2-4in compact speaker. 93mm length tube is suitable for 5-6.5in compact speaker. 105mm length tube is suitable for 8in compact speaker. 123mm length tube is suitable for 8in compact speaker. Made of high quality ABS plastic, this product is sturdy and durable. The speaker port, also known as the sound tube and the air hole, is often used in the ported speaker. It mainly suppresses the airflow sound of the speaker in the box and overlaps the sound pressure radiated in front of the speaker to produce a effect. Specifications: Material:ABS Color:Black Length:43mm/1.7in,93mm/3.66in,105mm/4.13in,123mm/4.84in,(Optional) Package Includes: 2x Speaker Inverter Tubes note: Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.