Vintage 70s sleeveless Psychedelic maxi dress

vintage 70s sleeveless Psychedelic maxi dress. This hung in my 90 year old grandmother’s closet a LONG time. If it fit me, I’d not be selling it. No size nor materials tag but feels polyester. Black sash Back zip 16” side slits Measurements approx flat lay Pit to pit 17” Waist 15.5” Length 53” Silver metal decorative details down front Such a classic!