You are buying a used Trek 850.
94th in the production line for this size and model.
First mountain bike model Trek made.
Serial #064555 Ref# 139940
Unfortunately the handlebars, stem, seatpost, and saddle are not original.
Tubing: Tange Champion Chromium Molybdenum Steel Tubing.
Frame size is actually 19.75"
Component Spec as follows-
Derailleurs: Suntour Mountech
Crank: Sugino Aero Mighty Tour Triple
Wheels: Suntour Hubs Laced to Araya rims, both black anodized finish.
Shifters: Suntour Power Shift
Brakeset and levers: Dia Compe GC980 Cantilever
Headset: Tange Levin
Some minor surface corrosion on frame and parts, see photographs for details.
No accidents dents or dings.