This is the timeless Sawyer gown from BHLDN, size 0. I am the original owner; I am 5'7", 130 lbs, size 34A bra. I will say that I initially bought the size 2 because my waist is more like 26.5-27", but because this dress is backless, the smaller waist still fit me. Alterations: shortened a couple inches, and I had a bustle added. I almost didn't even need to wear a bra, but I ended up earing stickies. The dress was very comfortable, good quality and breathable fabric. Can be worn with or without a decorative belt - I went without. I have the original protective bag as well.
Please note that I did NOT dry clean the piece after wearing it, because I figured whoever bought it would want to do their own cleaning. It only had typical wear/soiling from brushing the floor all evening, no major stains or anything (photo provided of hem).