Sinn’s Cal. SZ02 UTC is a modification of their Cal. SZ02, itself based on the ETA/Valjoux 7750 design. As of 2025 Sinn uses the Sellita SW500 ebauche.
Cal. SZ02 is unusual in that it features a 60 minute counter subdial (rather than 30 minutes), and this version also adds an independent 24 hour hand. Very few chronographs combine these features.
The first appearance of Cal. SZ02 was in the 2006 model 303 Football Chronograph, launched to celebrate the World Cup in Germany. It was also used in the EZM 13.1 dive watch (with left-hand crown and small seconds at 3:00) and continues in the new 613 St. diving chronograph.
The Cal. SZ02 UTC was introduced in 2025 in the Sinn 613 St UTC and represents a combination of Sinn’s SZ series features not seen before: 60 minute chronograph plus UTC hand.