The IWC Da Vinci Perpetual Calendar IW3921 was launched in late 2016 in anticipation of SIHH 2017. It marks a return of the style of the original 1985 Da Vinci Perpetual 3570, with a stepped round case and movable lugs. The IW3921 has a case with a diameter of 43mm and a height of 15.5mm, which houses the self-winding caliber 89360 with flyback chronograph and perpetual calendar. Reference IW3921-01 has a red gold case and a silver dial. It is fitted with a brown Santoni strap.