Inside the watch is a Landeron cal. 149, a cam-lever chronograph and one of the few Landeron calibres with a traditional operation ie. qualitywatch.co the top pusher starts and stops the chronograph and the lower pusher performs the reset. replica watches The more commonly used 48, 51, 148 and 248 calibres were designed such that the top pusher starts that chronograph and the lower pusher is used for both the stop and reset functions.