http://www.ebay.com/itm/271226589335
This vintage swimsuit was made in the 1960s by Jantzen. They are made of nylon, and have an elasticized drawstring waist. They are lined in the front. They come in the original ventilated plastic bag.

Waist (unstretched): 12″ (doubled = 24″)
Waist (stretched): 18″ (waist = 36″)
Side Seam: 8-1/2″
Rise: 12-1/2″