Mid 80's SIGMA made for C.F. MARTIN & CO. Model SDM-18 from Korea. Solid Sitka Spruce Top - Back & Sides laminated Mahogany Neck Mahogany low profile. Near Mint Conditions comes in Hard Case code AC120

 Body size: D-14 fret - Construction: Dovetail neck joint - Top: Solid Sitka Spruce- Back & Sides: Solid Mahogany - Neck: Mahogany, low profile - Saddle and saddle nut: bone - Fretboard & Bridge: Ebony - Scale length: 25.4" (645 mm) - Neck width at nut: 1-11/16" (42.9 mm) - Tuning Machines: Chrome Closed - Finish: high gloss

https://en.wikipedia.org/wiki/Sigma_Guitars