Long in my possession, this has been my favorite 18k gold pocket watch. I used to have a lot of them. I'm not a watch dealer, but we used to stock and sell vintage Rolex, Patek Philippe and Cartier gold watches and kind of got away from it. I've worn this one on a gold chain, just as a pendant watch several times. I admit, I know very little about it other than what can be gleaned by the imprints. At one point I did find the maker, but have lost that info. A designer watch, 19th century, it needs a watch key I do not have. I remember trying to test it, as it is not presently working. It would not wind and I simply noted it is in an overwound state. Then our watchmaker restorer we went to died, and here it's been ever since. Time to let it go. Whether it is a super-simple reset of the spring or just what, I do not know. Superb old thing, sapphire crystal and 18k gold with the most elaborate engraver's work in that monogram. As you see, it opens with an inner cover, so actually 3-hinged panels counting the crystal. The box shown was not original to it, but fits it perfectly and has been its protector for decades. Measurements noted on the photos.
Very good to excellent visually, age and type considered, as noted above I think the spring has been overwound. A simple enough adjustment for a qualified watchmaker, but I just never had it looked at, content to wear it on gold chain as a pendant. No loss or damage to the clockworks within, visually. I remember it was a pricey old thing. Someone will have a bargain, less than I paid.