Slingshot Stems
In 1982 Sakae Ringyo (SR) introduced two new “mountain bike stems”: the MTS-100 “slingshot” and the MTS-101 “golf putter.” The MTS-100 mated a typical BMX 4-clamp stem with a Bullmoose stem and came up with the Slingshot. It mimicked the look of bullmoose bars with more adjustability, lower cost and perhaps eliminating Ritchey's observed Repack rotation problem with the two clamps and four bolts on the bars1). Slingshot stems continued to be used long after Bullmoose bars faded from use in the mid 80's.
1983 Sakae Ringyo catalog, Page 10.velo-pages
SR Sakae Ringyo MTS-100 reddit.
Univega was perhaps the first to use the new slingshot stem.
The best selling bike of all MTBs from 1982→1987 was the Univega Alpina range, which used the MTS-100 from 1982→84 and then switched to the Nitto V-1 slingshot stem from 1985→86.
Stem from a 1982 Specialized Stumpjumper. Prettier than the MTS-101.
bikerecyclery.
Specialized used own-branded parts and their BMX 4-bolt stem was spec'd on Stumpjumpers from 1981→84.
1976 Cook Bros. Racing BMX. Four clamp stems had been used on BMX since the 60's, but the slingshots were new to MTBs.
bmxmuseum
Farr Headspace stem, available today at: ridefarr, pic from
bikepacking.