Omega is also engraved on front and back of the movement. 27.9mm is bigger and much more rare than the more common cal 26.5.
The movement finishing appears to contain a lot of effort in its detailing, which points towards this being a top end time piece for Omega during the period of manufacture. There is extra finishing not only on the top face of the movement plate but also on the back dial side of the movement.
The main plate in the balance area is also finished, as is the plate area for the wheels and pallet fork area. Even the main barrel area has extra finishing.
All this extra effort in finishing indicates Omega were trying hard with this watch. The case is in good condition and all snaps shut well with good hinge. There are some age related marks and small dents on the case back which are very minor. There are also some minor scratches on the movement plates. The enamel dial has several faint hairlines and a large filled repair in the enamel between 8 and 9.The marks on the dial are not really visible to the naked eye and can only be clearly seen under magnification. The case made for Omega by ALD is 32mm without the crown or lugs. The black leather strap is 16mm. The watch is working and the crown pulls out to set the hands and pushes in to wind. Time keeping has not been checked but balance looks to be running strongly. Overall this is a lovely antique watch by one of the best makers of the period, in solid gold. The 27.9 calibre movement is rare and a trench watch like this is not seen very often. The item "Omega Vintage Solid Gold Mens Gents 9 ct Carat K Trench watch Ww1 27.9 cal ALD" is in sale since Monday, August 27, 2018. This item is in the category "Jewellery & Watches\Watches, Parts & Accessories\Wristwatches".
The seller is "monkey9982" and is located in Peterborough. This item can be shipped to United Kingdom, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech republic, Denmark, Estonia, Finland, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Sweden, Australia, United States, Canada, Japan, New Zealand, China, Israel, Hong Kong, Norway, Indonesia, Malaysia, Mexico, Singapore, South Korea, Taiwan, Thailand, Chile.