TW IWC Portuguese series IW344207 perpetual calendar model The dial of the perpetual calendar is adjusted by a single crown. It is a small three-hand model with a new perpetual calendar module superimposed. It has a 60-hour power reserve and a 28,800-vibration frequency. It is made of stainless steel. The diameter is 42 mm and the thickness is 13.8 mm. The short lug design has functions such as calendar display, week display, month display, annual calendar display, and perpetual calendar. It is a classic formal watch.