The LK kits made by Lithonia Lighting come in two different styles, LED and non LED (halogen/Incandescent). With these light sources being used with the recessed trim there comes a point where you may encounter insulation in the ceiling space and this is where "Insulation Contact" comes into play.
With certain light sources, such as Incandescent and Halogen, it is not advisable to have insulation on top of the recessed housing as it prevents the heat from dissipating and will cause the fixture to overheat and fail, therefore the standard is three inches away from the housing. This is called "Non-IC" or non-insulation contact rated.
When using LED as the light source in our recessed kits, since they are cooler running as compared to incandescent and halogen sources, they can have insulation put on top of and around in close proximity to the housing and does not require the three inch spacing that would be needed were it another light source. This is considered "IC" rated or insulation contact rated.