The top of the line Topcon was the Navy's 35 mm camera from the early 70s to the mid 70's, lots of nice features for the day, but less expensive than Nikon or Canon. From what what I recall Topcon did not hold up under daily use and by the late 70s the Navy moved to Canon. the Topcons that are engraved U.S Navy are very collectable, the other are not.

Regards

Paul