This Metra ISO Double-DIN Installation Kit for 2004 through 2009 Mazda 3 is engineered to help you install an aftermarket 4 in. tall (double-DIN) radio into the original vehicle dashboard. This dash kit helps make radio replacement simple and is designed to match the original look and feel of the vehicle s dashboard. Installing an aftermarket radio can upgrade the sound quality and provide additional features the original factory radio couldn t offer but needs this dash kit to make it fit.