First of all, it isn't a chronometer, it's marked as a chronograph, (the definition of a chronometer varies depending on who you ask and and where!). However, it's just a centre seconds watch with a balance brake, the slider for which should be in the case band near 2 o'clock, and this stops the whole train, so not a true chronograph. It doesn't allow the centre seconds to be started, stopped and reset to zero independently of the rest of the train. They could be used as stop-watches for timing events, but you would need a second watch to tell you the time of day!
Many of these were made in Coventry and were much cheaper to produce than watches with true chronograph complications.