The Illinois SPECIAL watch movement, which was produced between the years 1916 and 1930, is a notable open face calibre designed and manufactured by LePhare and Zenith. This movement incorporates details outlined in the Swiss Zenith patent 62623. It features a bimetallic screw balance and utilizes a Breguet hairspring. The movement also includes several functions, namely a stem wind and pin set alarm, as well as a sub-second feature. The quantity of Illinois SPECIAL movements manufactured is estimated between 5000 and 6000, depending on the source, with equivalent LePhare models available, albeit lacking the typical Zenith balance cock.