Elastic is still good
Tag says fits 4 /7
I think that is closer to  a modern size 4
Made USA
100% polyester
Very rare find with department store and manufacturer tag still attached.

Waist unstretched laid flat measures 10.5 '' / 27 cm   

Waist stretched 14'' / 36 cm 

Waist to leg 6'' / 15 cm

I have similar but different pair listed also.

Please ask questions

Thanks for looking