Speaker adaptors are needed when you want to replace the original one in you vehicle. Speaker adaptors are designed to allow you to fit aftermarket speakers into your vehicle. They are easy to fit and ensure they fit securely. Universal speaker adaptors give you more speaker fitting options Material: Plastic Color: black Outer diameter: 24.4cm x 18cm (9.6 x 7.1 inch) Inner diameter: 22.4cm x 15.3cm (8.8 x 6 inch) Thickness: 2.5cm/1 inch Application: for automobile's speaker repacking package include: 4x Car Speaker Adapter Mount Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.