This is an amazing swimsuit from the 1940s or early 1950s by Jantzen. 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: 18" unstretched to 21" stretched (46cm unstreched to 53cm stretched) - flat
Waist: 32" unstretched to 37" stretched (82cm unstreched to 94cm stretched) - flat
Hips: 36" unstretched to 44" (92cm to 112cm) flat
Length: 25" (64cm) - counting from the top of the cup to bottom, so, not counting the strap.
Condition: With signs of use but no big problems. The elastics are a little bit dry and they will probably need reinforcement in the future. No holes, stains, etc.