Eska was the brand name used by the Sylvan Kocher & Cie watch making company set up around the end of 1918. The company was created because there was perceived to be a growing market for wrist watches and Kocher wanted to be part of that growing industry.
Some quality wrist watches were forthcoming from the factory and although there were numerous brand names, this Company seems to be the one that has survived the longest. The firm mainly bought movements that were made by another firm, Ebauches SA and cased them in various types of cases to provide a wide range.
Both square and round cases were used and the movements varied between standard time keepers and chronographs, automatics day/date functions, moon phase and other complications.
For the collector, Eska is actually quite collectible. They made some watches with cloisonné enamel dials and these are very rare and command a high premium from collectors. Their complicated watches can be found with solid gold cases and they look superb. They are also reasonably priced and good examples can be found for less than $1000.
Good value, in my opinion.
Today's U.S. Auctions of Sale Items on eBay.