1940s cotton twill double side button athletic shorts.
Original tags attached. 
Blue with white trim and buttons. 
3 white buttons on each side. 
Felco athletic wear label. 
Union made; dry clean only or cold wash with synthrapol to avoid color bleed.
Best fits modern 8-12
29-31” waist with adjustable buckle
14.5” rise
42” hip below button placket
44” hip one inch below placket
13” across thigh opening