This is an amazing swimsuit from the 1940s or early 1950s by Heinzelmann. Fabric is cotton. You can wear it with straps or strapless.
Measures - Please make sure you double-check your own measures and compare them to the ones below.
Shoulder to shoulder: -
Armpit to armpit: 20" unstretched to 25" stretched (50cm unstreched to 64cm stretched) - flat
Waist: 34" unstretched to 46" stretched (86cm unstreched to 116cm stretched) - flat
Hips: 39" unstretched to 55" (100cm to 140cm) flat
Length: 33" (84cm) - counting from the top of the cup to bottom, so, not counting the strap.
Condition: With signs of use but no problems. Only a tiny pinhole only visible backlight.