The Best Precision Electric Latch Retraction Kit ELRK-4 PHI is an additional kit that allows you to convert an Apex 2000 Series panic bar from Best Precision from a regular function to an electric latch retraction function. This allows you to electrically lock and unlock the door. This can be done from a remote location such as a security station or an electronic card or key reader near the door. This particular kit os for a 4 foot long device. An ELR Conversion Kit REQUIRES a ELR150 Series Power Supply. The Best Precision Electric Latch Retraction Kit ELRK-4 PHI does not have a color as the parts of the kit are placed into the panic bar you are converting.