I bought 2 of these units to fit in a Dapol Class 142 DMU, which is described as light bar ready.
Yes, there is a socket in each of the DMU cars to plug in a light bar, but...
While these light bars may fit coaches, they are too long to fit in a DMU.
There are no instructions provided on how to fit the light bars in a DMU.
I ended up having to saw off the last 2 LEDs and their associated resistor to fit in the length of the car.
I also had to remove the foam in the body which sits above the decoder, because with it, the body would not fit back on the chassis. I put a length of tape over the decoder to provide some insulation from the light bar.
One of the LEDs is directly above the decoder. In my opinion there are too few LEDs and they are spaced too far apart.
They are also, on normal settings, too bright. I've seen comments from other users saying the same.
I found a CV setting that dims them, but there is some flicker.
They may be fine for coaches, but certainly not for a DMU.
Dapol should produce a different version which is suitable for a DMU
Easy to fit although needed some double sided sticky tape to keep it in place. I am using it with DC so locomotive (121 ‘bubble car’) needs a bit of speed for the voltage to be high enough to operate LEDs. Presumably this would not be a problem with DCC. Reasonably priced and effective lighting.