Technics 1200 Series Turntable Model Information

MK2 models
The SL-1200 Mark 2 was introduced in 1979. It was an update to the popular SL-1200 series. It again represented a culmination of Technics Turntable Innovations. It was dubbed as "The Middle Class Quartz Direct Drive". It was not released as a professional model, but became popular with pioneering hip-hop DJs. It soon found its way into discos as well as radio stations for airplay because of its vibration dampening ability and resistance to feedback.
The MK2 models were sold in Europe with different model numbers indicating a different color; the 1200 (silver) and 1210 (matte black). This was the same in the USA (and Japan) initially, however later the 1200 were available in both silver and matte black finishes.
SL-1200MK2 (released in 1979) comes in both silver and matte black (see above comment). Technics improved the motor and shock resistance, added a ground wire, and changed the rotary pitch control to a slider style. This is now the base model and is the oldest whose production was done until 2010. The older version of this model, which was sold in the 1970s and 1980s, has a large 4-inch-diameter (100 mm) plate where the RCA and ground wires enter the unit, while the newer version has a smaller 2-inch-diameter (51 mm) hole in the rubber where the RCA and ground enter. International versions of the SL-1200MK2 included switches for line voltage and frequency beneath the platter.   
SL-1210MK2 comes in satin black metallic finish only (see above comment), and is nearly the same in function as the SL-1200MK2, although some of the circuitry inside is updated to use fewer different types of pots and resistors. The Technics 1210 series also had a switch to change between voltages on the underside of the platter. It used to be unavailable from official Panasonic dealers in the United States.
SL-1200MK2PK has a matte black finish, and was only available in the USA.

MK3 models
SL-1200MK3 (released in 1989) has a matte black finish like the MK2, gold RCA plugs, and a small gold foil Technics label on the back. It was destined only for the Japanese market.
SL-1200M3D (released in 1997) has a silver finish like the MK2, a detached dust cover (no hinges), and no detent ("click") at the zero point of the pitch adjustment slider, allowing more precise control of pitch near that point. It also has a reset button, which sets the pitch adjustment to 0, regardless of the actual position of the pitch adjustment slider. In addition the M3D series have a couple of unique details, the brand and model label is printed in a single line instead of two, and the stroboscopic light is still red but with a slightly orange tone.
SL-1210M3D is the same as the SL-1200M3D except with a matte black finish like the MK2, except for the voltage switch.

MK5 models
SL-1200MK5 (released in 1 November 2002) has a silver finish like the MK2, increases the range of anti-skate settings from 0–3 grams-force (0–30 mN) to 0–6 grams-force (0–60 mN). Also has a white LED target light (previous versions only had a globe and burnt out over time). Current MK5 models have a removable lid with magnets as opposed to the MK2 and MK3 removable hinged lid.
SL-1210MK5 has a matte black finish like the MK2, and is exactly the same as the SL-1200MK5, aside from the voltage switch, like the other decks in the 1210 series.
SL-1210M5G (released in 1 November 2002) has a glossy piano-black finish with silver speckles, was a special 30th-anniversary edition. It was initially launched in Japan only (together with the MK5) but then became internationally available. The difference from the MK5 model is the ability to switch between ±8% and ±16% ranges for pitch adjustment, and the pitch control in this model is completely digital. It also features blue target lights and blue pitch-number illumination. The brake strength potentiometer, although still located beneath platter, can now be adjusted, unlike previous models, without the need for a screwdriver thanks to the addition of a small plastic knob. Minor improvements over Mk2, Mk3, Mk4, & 1200LTD also include improved tonearm mounting and oxygen-free copper wire being used for the signal, improved vibration damping in the body, improvements to the pitch control accuracy and better LEDs.