The Gruen 555 watch movement is a quartz movement with flatline hours, minutes, seconds, and date functions. It offers very high precision due to thermocompensation and includes a 100-year perpetual calendar displayed in a window, valid until 2099. The movement allows for an instantaneous change of date with a precision jump of approximately 2 minutes. Additionally, it has the ability to momentarily display the month and cycle of the year by the date indicator when the crown is pressed. The movement features a quartz mechanism, perpetual calendar functionality, and a time zone display.