L-90 / OBL-900

The L-90 magnetic electric guitar pickup was released by Lawrence Sound Research (LSR) in 1976, the precursor to the L-500.

From the ad pictured below "L-90XL  Replacement pickup developed and built in Germany in 1968 by Bill Lawrence and reissued in 1977 ".  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