Source 4WRD on a Source Four Junior
Source 4WRD retrofit cannot be used on a Source Four Junior fixture body for several reasons.
The Source 4WRD retrofit will not fully seat on the fixture body, so the LED array will not be in the reflector and no light will be projected. In addition the user would be exposed to high voltage connections on the Source 4WRD retrofit engine when it is installed, which would be a danger to the user and others in the space.
Source 4WRD is only for use on the standard Source Four body.