1960 First Day Cover Satellite Echo Progress in Space

Hello, here I have a 1960 first day cover Satellite Echo Progress in Space. The measurements are, 6 1/2" x 3 3/4". very good condition. If you have any questions, please do not hesitate to ask, I will get back with you promptly. Please take a look at the many other first day covers that I have in my store. Thank you for stopping by and have a great day of-1-7-D in three ring binder