Listed is a vintage Park Avenue Lingerie (M Collection?) RN 97190 brick red soft velvet panty and matching bra set. Bra is a 34A, with removable push up pads, back closure, adjustable straps. Bow on gore. 
Matching bikini high cut panty, size large (but appear to run a little small). Excellent vintage condition. Elastic waist/legs has excellent stretch and return to shape, removable pads in bra are intact. Slight ruffle on strap, but still has good stretch and return to shape. 80% nylon, 20% spandex.

Panty, lying flat, waist across unstretched 11", 18" stretched. Top to bottom 11.5".
Thank you for looking!