Clymer windshield spot light bulbs type?

Have pair of Clymer windshield spotlights, does anybody know what bulb type is used in them? I know they use single filament, dual contact bayonet base, 6V bulbs. I have one original bulb, saying Mazda 6-8V, but unfortunately the type description is wiped off. The problem I have the diameter of bulb the base is not usual 15mm (that would allow me to use standard bulb w/ BA15D base) but something around 1/2". I cannot alter that as the design of Clymer lamp does not allow that.

Thanks for any help offered.

I know the spotlight you mean but I don't know the bulb. It was probably a standard headlight bulb of 1920.

I went through tens of automotive bulbs offered on ebay, if they are single filament, dual contact and reasonable candle power, their sockets always were 15mm. I do not want to spend more time with this try and error research, hope anybody here can provide info about the right type to look for.

Try doing your search here at Don's Bulbs.

http://www.donsbulbs.com/cgi-bin/r/t.pl/bulbdatasearch.html

Yes, I found Dons place. For example for 1134 bulb (32 CP) the only socket specified there is BA15D (dual contact, 15mm dia). There is no single mention about 1/2" socket diameter occurence, not talking availability. I found a vendor on ebay that positively confirms 1134s he has for sale are 1/2" socket diamater. There is other vendor offering 1134s in exactly the same looking factory box and hers are (said to be) 15mm..... My theory is that manufacturers produced 1/2" versions before the common standard 15mm came into place; since then they simply upgraded the sockets to the standard and 1/2" sockets disappeared from automotive world...