Found this in the UK version of the GCR
Red Warning Light
5.1. A rearward facing red warning light of a minimum of 21
watts, with surface area minimum 20cm2, maximum 40cm2, or
of 21 watts with a surface area minimum of 50cm2 and with
lens and reflector to EU Standards, must be located within
10cm of the centre line of the vehicle and be clearly visible
from the rear. Vehicles fitted with full width bodywork may
alternatively use two lights equally located about the vehicle
centre line. An alternative light unit of equal or enhanced
constant luminosity or LED lights that are either homologated
by the FIA or comply with relevant EU Regulations may be used.
5.2. The warning light must be switched on when visibility
conditions are reduced, or as detailed within championship
and/or event regulations, or when so instructed by the Clerk of
the Course.
They still dance around the watts when we need candlepower or luminosity.
I give kudos to the Afterburner guys to get FIA approval - but worry about the cost of certification...
Still think self certification is better that Enterprise certification, but at least that keeps it in the Club. "SCCA Approved" Could be a new profit stream (did I really say that????

)
ChrisZ
BTW - I wrote my letter - has everyone else?