A light emitting diode (LED) module is in thermal communication with front and back heat sinks for dissipation of heat therefrom. The LED module is physically held in place with at least the back heat sink. A mounting ring and locking ring can also be used to hold the LED module in place and in thermal communication with the back heat sink. Key pins and key holes are used to prevent using a high power LED module with a back heat sink having insufficient heat dissipation capabilities required for the high power LED module. The key pins and key holes allow lower heat generating (power) LED modules to be used with higher heat dissipating heat sinks, but higher heat generating (power) LED modules cannot be used with lower heat dissipating heat sinks.