This Longines is not mine but I bought it for my eldest son when he passed his professional exams about ten years ago. I'm looking after three of his watches while he has work done on his house.
There was a chap in the US that made them, but he doesn't seem to be around these days. Similar come up on eBay This chap makes real beauties, including original style buckles in silver.
First time being flown in the pointy end today...newly purchased railroad grade 23j Elgin B.W. Raymond with wind indicator...good times!
So I'm guessing this was a military solution to broken crystals? Where in heck did you find this? What's its history?