Bought some facelift lights from our german friend

(came within 4 days btw-very impressive)

Theres a tiny little circle thing that comes with them. Must be important cause it's in a bag sellotaped to the unit. Anyone know what it's for?

Might be obvious when I try to fit them at the weekend.

I'm guessing I don't use the existing indicator bulb too? And the order of the lights is 'REverse' above 'indicator'?