SME is a brand name of an English company that produces high end tonearms and turntables, whose name has become synonymous with the industry standard detachable headshell mount.
 SME was founded by Alastair Robertson-Aikman  in 1946 under the title The Scale Model Equipment Company Limited to manufacture scale models and detail parts for the model engineering trade. It was During the 1950s the company moved away from model making to precision engineering, principally parts for aircraft instruments and business machines.
 In 1959, Robertson-Aikman required a pick-up arm for his own use and an experimental model was built. It received such an enthusiastic reception from friends in the sound industry that it was decided to produce it commercially and the first SME precision pick-up arm appeared in September 1959. Production was 25 units per week composed entirely of individually machined components. In 1961 a new factory situated in Mill Road, Steyning, Sussex was opened and the Company's name was changed to SME Limited, a less committal title to suit its new activities.
 In December 2016 the company was acquired by Ajay Shirke with a view to preserve the brand's legacy and extend research and development activities, appointing a new CEO and a distributor for the UK market, Padood.
 In May 2018 the company acquired the rights to the Garrard Transcription Turntable brand as well as Loricraft Audio, the only officially authorised Garrard service agent. Intending to develop the Garrard audio brand in the near future.
 The Series II arm was SME's first arm. It came in two variants the 3009 and 3012 (9" and 12" respectively) tone arms which were widely adopted for audiophile and broadcast use during the 1960s and 1970s, at the higher end of the market. These arms featured a polished, bright-anodised aluminium  main tube with a lightweight headshell, knife edge horizontal bearings, and an anti skating bias provided by a weight that hung by a nylon filament.  
Versions  were produced with both fixed and interchangeable headshells; the SME headshell mount (based on an Ortofon design) became the de facto industry standard, and is still widely used today on consumer and especially DJ decks. Audiophile arms today tend to not use the SME mount, but this is not due to other standards replacing the SME but because audiophile arms now tend to not have interchangeable headshells at all  in an effort to reduce mass and improve rigidity, though at slight expense of user flexibility.   
Some cartridges were produced that mounted directly into the SME headshell mount of the arm (rather than into a headshell), notably from Ortofon.
 The Series III was introduced in the late 1970s incorporating changes from the Series II models (which continued in production) covering both styling and its exceptionally thin and lightweight main tube, the entire arm being interchangeable rather than just the headshell. The Series III had very low effective mass to fit high compliance cartridges such as the Shure V15 IV.
Although technically advanced, the Series III never achieved the market dominance of the Series II.
 The Series V arm launched in 1986, was developed as a medium mass arm more suited to emerging moving-coil cartridges with lower compliance than previously available moving magnet cartridges. The removable headshell was eliminated, and the horizontal knife bearing was replaced with ball bearings (grade ABEC 9), both in order to provide a more rigid structure for the cartridge.
 The Series IV arm launched in 1987 was a variation of the Series V for a cheaper price point. It was mechanically and electrically identical to the Series IV with the exception of using lower grade (ABEC 7) bearings than the Series V and due to the omission of the damping trough used in the Series V.
 The Series 300 arm launched in 1988 was a lower specification arm based on the same design concept as the Series V and IV arms. It still used a magnesium alloy arm, but had a removable headshell. It came in three models 309, 310 and 312 with lengths of 9, 10 and 12 inches respectively.
 The M10 arm launched in 1999 is derived from the Series 300 Model 309 (but with lower grade ABEC 1 bearings) is only for use with the SME Model 10 turntable.
 The Series M2 arm launched in 2004 is the companies lowest spec currently available, and the only arm made by SME that can be bought separately at this time. It comes in three models with lengths of 9, 10 and 12 inches.
 The Series VA arm is only available on the Model 60 turntable. It is an advanced version of the Series V tonearm which has been extensively sonically improved by use of a non-metallic tonearm CNC machined from an advanced polymer resin material with high density and high rigidity properties. The Series VA tonearm tube is acoustically inert with a significantly reduced resonance signature, optimised effective mass and a wide cartridge balance weight range.
 
 The Model 30 was SME's first turntable, launched in 1991. It was their flagship model up until the launch of the Model 60 in 2022. The turntable weighs 42kg (excluding arm, power unit or speed control unit). In subsequent years the 30 MkII, 30/12 and 30 Diamond models were released.
 The Model 20 was SME's second turntable, launched in 1992. It was inspired by the Model 30 and designed to meet a lower price point. The turntable weighs 26kg (excluding arm, power unit or speed control unit). In subsequent years the 20 MkII  and 20/12 models were released.
 The Model 10 was SME's third turntable, launched in 1999. It was a totally new design from the 30 and 20, and was SME's "entry level" turntable, which was intended to be sold with arm included (either M10 or IV.Vi). The turntable weighs 16kg (excluding power unit or speed control unit). 
 The Model 15 was SME's fourth turntable, launched in 2015. It was an upgraded design of the Model 10 design, with improved materials and using a suspension based on the one used in the Model 20. The turntable weighs 19kg (excluding arm, power unit or speed control unit). 
 The Model 60 is SME's fifth turntable, launched in 2022. It is their current flagship model and a comprehensively new design. The turntable is only available with the Series VA tonearm. The turntable weighs 48kg (excluding power unit or speed control unit).