In some of our user documentation we gave the wrong name for the lamp socket in all MAC Viper fixtures. Socket type PGJ28 is not correct.
The correct designation for the lamp socket in all MAC Viper fixtures is: PGJX36.
We corrected the lamp socket details in MAC Viper fixtures' online specifications in June 2013. We are currently updating our user documentation, but the documentation for your product may still list the incorrect lamp socket.