unusual KLG plug ID needed

[mini-me]

I thought I could cross ref most old plugs, but now I have picked up a mica bodied KLG 646, with a non detachable body; 14mm short reach, 3 fins turned on body and with that disc electrode. Only other markings are two small  astericks and RR .
 obvously RR brings to mind rolls royce;doubt it, or road race

I can't find it in any cross ref lists, any one got any ideas?

[L.A.B.]

Try: The Green Spark Plug Co.: http://www.gsparkplug.com/

[mini-me]

first place I looked, no info
can't even find it on google bar one mention in a Motorsport link which just wants me to subscribe.

[L.A.B.]

first place I looked, no info

You could still ask them?: https://www.gsparkplug.com/contacts

[mini-me]

True.

[murdo]

Sounds interesting, any photos?

[cardan]

It's a reasonably cold racing plug, probably from the 1930s.

http://www.oldengine.org/members/diesel/Plugs/equiv.htm

Here's the long reach equivalent, yours for 10euro:

www.ebay.ie/itm/152005778589

Leon

[mini-me]

thats it Cardan, thanks