WEM stands for Watkins Electric Music. W.E.M. had a number of amplifiers and speaker equipment produced during the mid 1970s. The company has remained the same under Charlie Watkins, but in the late 1960s and early 1970s the amplifiers and P.A. equipment started to appear with WEM on the label. These amps were produced and England and many of them have stayed over there. A few may appear in the U.S., but until more have been circulated it is difficult to price these amps accurately. Some of the more popular models were the Dominator and the Westminster (mainly because of their popularity in the 1960s. Look for more information or updates in further editions of the Blue Book of Guitar Amplifiers.
See WATKINS