SME is known as a premium maker of tone arms and analog accessories for turntables. Formed in 1946 as the Scale Model Equipment Company Limited, SME began as a manufacturer of scale models and parts. In the 50's, the company started manufacturing the more specialized parts, eventualy the tonearms and turntables they're now known for.
Notable SME products include:
SME M2 Tonearm SME Model 10 turntable SME Model 309 Tonearm
HomeTheaterReview.com's SME product reviews include:
SME M2 TonearmSME Series I, II, III TonearmsSME 20/12 and 312S TonearmSME Series 30 Turntable
There is also a history of the brand on Wikipedia.
Similar to SME are companies such as Clearaudio, Simon Yorke, and Linn.