The Technics SL-J2 is a quartz-controlled direct-drive fully automatic turntable system produced by Technics between 1984 and 1988. It features a linear tracking tonearm with an optical sensor that allows for the kind of track-skipping more typical of CD players. The sensor also detects the size of the record sitting on the platter (7-inch, 10-inch, or 12-inch), which allows the needle to drop precisely on the first track.
Product description.
From the original Technics SL-J2 brochure:
"Who else but Technics could put so much high performance, and so many convenient features in such a slim body? The SL-J2 features the outstanding rotational speed accuracy of quartz-referenced direct drive, and a linear tracking tonearm for perfect tracing accuracy. The convenient skip/search/direct access function allows you to skip over selections you don't want to hear. A separate, easy-to-read Music Select LED confirms your skip/search commands."
Features.
Also from the original SL-J2 brochure:
Technical specifications.
Type: fully automatic turntable ;br ;
Drive method: direct drive ;br ;
Motor: DC motor ;br ;
Drive control: quartz phase locked ;br ;
Platter: 300mm aluminium die-cast ;br ;
Speeds: 33 and 45rpm ;br ;
Wow and flutter: 0.025% WRMS ;br ;
Rumble: -78dB ;br ;
Tonearm: linear tracking tonearm with 4-pivot gimbal suspension ;br ;
Effective length: 105mm ;br ;
Cartridge: moving magnet ;br ;
Tracking force: 1.25g (+-0.25g) ;br ;
Replacement stylus: EPS-30ES ;br ;
Dimensions: 315 x 88 x 315mm ;br ;
Weight: 4.3kg ;br ;
Similar models.
The Technics SL-10, produced by Technics between 1981 and 1985, was the first linear-tracking turntable to feature direct drive. 
The SL-10 is also notable for being in the permanent collection of the Museum of Modern Art in New York.
Other direct-drive linear tracking turntables produced by Technics include the SL-15, SL-7, SL-6, SL-5, and SL-V5.