Sinn has long used the Valjoux 7750 movement for their chronograph watches, but began reworking the movement in the 2003 as the SZ01. This was followed in 2014 by this Cal. SZ03. In addition to a 60 minute (rather than 30 minute) chronograph counter at 12 00, as in Cal. SZ02, Cal. SZ03 features an unusual calendar arrangement Windows at 12 00 show the day of week and month, a central pointer shows the date, and the subdial at 6 00 shows the week number.