Excellent quality work. I am proud to own an M-73 by Pyser Optics, from, I believe, the first production run in 1973 (no serial number and M-73 PAT APPL on the back) The only problem I have is that it's such a work of fine craftsmanship I am almost afraid to use it. I have owned it for 45 years and am passing it on to my mountain mad daughter who drools whenever she sees it. Thanks for making it possible for her 40th birthday.