The Felsa 4015 watch movement is a manual wind movement with a pin-lever escapement. It features a sweep second hand and displays the day and date. The watch also includes a calendar function. The Felsa 4015 movement was commonly used around 1975 and is labeled with calibre designations of 420 or 420/425. The available information on the correlations between calibre designations and features is not very reliable, but this does not significantly affect the functionality of the watch movement.