from  Volume 90 of the American Science and Surplus catalog:

'and i quote...'
LED LAMPS
What?? Lamp-based, multi-chip LEDs, if you want to be precise.  Each 
is a lamp like device, 3/8" dia X 1" long O.A.  It can be plugged 
into a standard single contact bayonet base socket.  But the 'lamp' 
is actually an LED or cluster thereof.  (We are not sure)  Each has a 
removable frosted hemispherical dome, and they are called Data 
Dsiplay Model MB400.  Whic is confusing because they come in a 
variety of voltages, currents, and colors.  With high intensity, 
strong color and low current draw they are really cool.  The 15 
volters work on 12 VDC but are slightly dimmer.

6 VDC, 65 MA
23136  LED lamp, Green  $2.25
23139  LED lamp, Amber  $2.25
23142  LED lamp, Red        $2.25

15 VDC, 25 MA
23145  LED lamp, Green  $2.25
23148  LED lamp, Amber  $2.25

23154  Bayonet socket  $2.00 for 6

phone orders 708/982-0870, 
3605 Howard St., Skokie, IL  60076