Plastic part remaining in a K8059 kit

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1

Hello,

I’ve just assembled 3 K8059 transmitter kits, but I still wonder what is the use of a small plastic part (a 3x3x3 cube, with a notch all around) which has the same color of the housing.
Somebody to help me ?

Regards,

JL

2

It will be the LED distance holder, normally he must be mounted between the PCB and the LED.