Vintage Chocolate Brown Button Down Blouse

Chocolate brown fitted button down short sleeve blouse. Vintage paper tag. Brand Erena. Probably came in a 2 piece set originally but I just got the top at the vintage shop. Wrinkly/starchy material but tag is faded so I don’t know the exact material. No stains/damage. I just don’t wear anymore. Measurements are laying flat pit to pit & length.