Singlet by wrinqle, the in-house brand of inoue pleats co. Made from a slightly pinkish red, pleated polyester fabric, it is dramatically small when laid flat but stretches substantially to accommodate the body. A yellow and green version of this singlet is available here.

Size M - L (JP womens/unisex), may fit smaller
Check measurements to confirm fit
All measurements taken flat
Garment has stretch

Shoulder width: 24.5 cm
Width (at underarms): 26 - 44 cm
Length (neck to hem): 49.5 cm
Hem width: 25 cm

100% polyester
Made in japan

More wrinqle items here. Or read (a little) about inoue pleats co.