Sellita SW535

	Brand:	Sellita, Sinn
	Family:	Sinn SZ
	Height:
	Jewels:	23
	Reserve:	hours
	Frequency:	28,800 A/h
	Winding:	Automatic, Bi-Directional Automatic Winding, Central Rotor Automatic Winding
	Diameter:	30.00 mm
	Complications:	2-Button, 24 Hour Hand, Cam Switching Chronograph, Chronograph, Date, GMT Hand, Hacking Seconds, Hand Winding, Independently-Adjustable 24 Hour Hand, Quick Date Correction
	Hands:	60 Minute Chronograph Hand at 6:00, Central 24 Hour Hand, Central 60 Second Chronograph Hand, Central Hour Hand, Central Minute Hand, Date Window at 3:00, Small Seconds Hand at 9:00

Distinguishing Technical Characteristics
Central-Rotor Automatic Clockwise Balance Cock Balance at 1:30 Central Rotor
Production: 2025 – Current
1910s	1920s	1930s	1940s	1950s	1960s	1970s	1980s	1990s	2000s	2010s	2020s

Sellita developed Cal. SW515 and SW535 based on the Sinn Cal. SZ02, which was previously manufactured on an ETA/Valjoux 7750 ebauche but moved to the Sellita SW500 base in the 2020s. Coverage of the 2025 introduction of Sinn’s 613 models uses the names “SW515” or “SW535” and “SZ02” interchangeably, though the former names are more appropriate since these movements are produced by Sellita.

These movements are unusual in that they features a 60 minute counter subdial (rather than 30 minutes). This was a hallmark of most of Sinn’s SZ family movements, and was inspired by the Lemania 5100, which featured a central 60 minute chronograph hand like the original Sinn Cal. SZ01. This version also adds an independent 24 hour hand. Very few chronographs combine these features, and none has this particular arrangement of hands.

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). The Sellita Cal. SW535 was introduced in 2025 in the Sinn 613 St UTC and is the first Sinn SZ-derived movement to feature an independently-adjustable UTC hand. Unlike the similar Cal. SW515, the UTC movement lacks a day window.

SW535 Operation

The crown of Cal. SW535 has four positions:

0. Turn counter-clockwise to screw down for enhanced waterproofing
1. The movement can be wound by rotating the crown clockwise (about 40 turns to completely wind it)
2. Clockwise: Quick date advance (do not use between 9 PM and 3 AM); Counter-Clockwise: Advance the independent hour hand
3. Hacking seconds; Set the running time

Note that the date is connected to the running time rather than the UTC hand.

Sinn SZ01 Family of Movements

Sinn began working on their in-house modifications on the Valjoux 7750 base in 2003, introducing their Cal. SZ01 in the 2006 World Cup Football timer and EZM 1.1. These included a central chronograph minutes hand like the famous Lemania 5100. This was quickly followed by the Cal. SZ02, which moved the chronograph minutes to a subdial at 12. Cal. SZ03 (2014) and Cal. SZ06 (2019) add a week number counter or moon phase as well as a day and month window, while Cal. SZ05 (2011) moves the chronograph 60 minute subdial to 3. As of 2025, Sinn is phasing out their SZ series in favor of similar movements (Cal. SW515 and Cal. SW535) produced by Sellita.