Sinn SZ01

	Brand:	Sinn
	Family:	Sinn SZ
	Height:
	Jewels:
	Reserve:	hours
	Frequency:	28,800 A/h
	Winding:	Automatic, Central Rotor Automatic Winding, Counter-Clockwise Automatic Winding
	Diameter:	30.00 mm
	Complications:	2-Button, 24 Hour Hand, Cam Switching Chronograph, Chronograph, Date, Hacking Seconds, Hand Winding, Quick Date Correction
	Hands:	12 Hour Chronograph Hand at 6:00, 24 Hour Hand at 3:00, Central 60 Second Chronograph Hand, Central Chronograph Minute Hand, Central Hour Hand, Central Minute Hand, Date Window at 4:30, Small Seconds Hand at 9:00

Distinguishing Technical Characteristics
Central-Rotor Automatic Clockwise Balance Cock Balance at 1:30
Production: 2003 – Current
1910s	1920s	1930s	1940s	1950s	1960s	1970s	1980s	1990s	2000s	2010s	2020s

Cal. SZ01 is an automatic chronograph movement based on the ETA 7750 but modified with a central chronograph minute hand. The movement was designed to replace the Lemania 5100 in Sinn’s EZM mission timer watches, which had a similar arrangement of hands.

At the Basel fair in 2003, Sinn showed a prototype of an “in-house” watch movement to replace the classic Lemania 5100 automatic chronograph, which was going out of production. Called Cal. SZ 01, it featured a central 60 minute chronograph hand like the Lemania movement but was based on the ETA 7750 ebauche. This movement was intended to be introduced to market in 2004 but proved very difficult to develop. It did not ultimately appear until September 10, 2011 in the Model EZM 10.

The derived Cal. SZ02 was quicker to develop. Rather than a central chronograph minute hand, it features a 60 minute chronograph subdial, a rarely-seen feature. Launched in late 2005 for the Model 303 World Cup Football chronograph, this movement was made famous in the EZM 13 and EZM 13.1. These watches featured left-side crowns with running seconds at 3 and the chronograph minute subdial at 6 but no date or other functions.

Cal. SZ01 was used in the following models:

• Right-side crown, 24 hour dial at 3, date at 4:30, chronograph 12 hour at 6, small seconds at 9
  • 2011 Sinn EZM10
• Right-side crown, date window at 3, 12 hour counter at 6
  • 2012 Sinn 140 “Space Chronograph”
• Right-side crown, date window at 3, small seconds at 9
  • 2021 Sinn 717 Cockpit Wristwatch
• Left-side crown, date window at 3
  • 2022 EZM 1.1

Although Sinn often deployed this movement with a left-side crown, the convention on this website is to list subdial locations based on a right-side crown orientation. The following is the arrangement of hands with the crown at right:

• Central hour and minutes hands
• Central chronograph seconds and minutes hands
• Running 24 hour hand at 3
• Chronograph 12 hour counter at 6
• Small seconds at 9
• Date window at 4:30

Some or all of these subdials were often omitted, as on the EZM 1.1 (no subdials, left-side crown) or Sinn 140 (we hour counter at 6, date window at 3, right-side crown). The Sinn EZM10 is the only watch to feature all of the features and subdials of Cal. SZ01.

Sinn SZ01 Family of Movements

Sinn began working on their in-house modifications on the Valjoux 7750 base in 2003, introducing their Cal. SZ02 in late 2005 for the 2006 World Cup Football timer. Cal. SZ01 included a central chronograph minutes hand like the famous Lemania 5100 and appeared in 2011 in the EZM10. 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.