read the unit manual here - Brash Imports

InstallBefore installing the receiver, fit it in the suitable place of your car. Then connect thecorresponding speakers and electrical connections. When yoursystem is operated properly, follow theFigure 2instructions installationINSTALL THE UNIT1.Use the two keys to remove the bracketfrom the unit, as in Figure (1).2. Put the bracket into the installation hole,bend over the slices to secure the bracket,as in Figure (2).3.Put the unit into the installation hole via thebracket, until the unit is fixed well, as in Figure (3).Installation bracketREMOVE THE UNITInsert the keys into the small gaps inthe right and left sides of the unit atthe same time. Link the keys to theslices and then pull out the unit lightlyto remove it from your car, and thenpull out the connection plugs.Figure 1Figure 3The installation hole with bracket5