L-100

 The L-100 was introduced by LSR before the L-500.  Featuring bobins and phillips screw-pole pieces,  did not have the 'tub' or suround found on the L-500 and later L-350.

 From the ad pictured below "L-100  Reissue of the 1965 Bill Lawrence two sound pickup-- the first hot replacement pickup ever made ".  (I guess Bill developed this while at Lawrence Electro-sound?)

Advertisement/photos as they appeared in Guitar Player magazine, July 1979.

Photo of Aerosmiths Joe Perry and Brad Whitford credited to Ron Pownall Boston