Lighting module with keyed heat sink coupled to thermally conductive trim

A lighting module, comprising:

• a heat sink comprising:
• a rear end face;
• a sidewall coupled to the rear end face and defining an interior cavity, the sidewall having at least one exterior width dimension such that at least a portion of the sidewall proximate the rear end face fits into a space having a width of less than 2.4 inches;
• a front end face that surrounds a first open end of the interior cavity;
• at least one connecting mechanism to couple a trim to the front end face of the heat sink;
• and
• at least one keyed feature, disposed on the sidewall of the heat sink, to provide sufficient clearance between the heat sink and a surface of an enclosed space such that the sidewall of the heat sink is insertable into the enclosed space without contacting the surface;
• a light source positioned inside the interior cavity of the heat sink and including at least one light emitting diode (LED);
• and
• a driver, positioned inside the interior cavity of the heat sink, to receive electrical energy and supply regulated electrical energy to power the light source.