Very few Betas came with linear stereo. More correctly it was two separate channels recorded by two stationary heads located in the ACE head assembly. It was mostly limited to the professional units such as the Sony GCS-50, SLO-383, SLO-420 and SLO-1800. The GCS-50 and SLO-1800 also recorded in Betahi-fi stereo but only the model GCS-50 allowed selecting the two linear tracks separate from the Betahi-fi stereo recording. The SLO-1800 was a studio duplicator designed for producing pre-recorded tapes. It started with linear stereo tracks but these were abandoned in mid-production. Presumably this capability was for making stereo tapes for the only consumer linear stereo Beta ever made, the Marantz VR 200. Made by Sanyo it was introduced just a few years prior to Betahi-fi.