Frederic Piguet Caliber 21

Manufacturer	Frederic Piguet
Caliber Number	21, FP-21, FP21
Movement Type	Mechanical, manual-wind
Lignes	9”’
Diameter	20.4mm
Height	1.73mm
Jewel Count	17/18 jewels
Beat Rate / Frequency	21,600 bph / 3 Hz
Lift Angle	53 degrees
Power Reserve	42 hours
Anti-Shock Device	Kif-Duofix
Balance	3-spoke monometal balance wheel with flat hairspring
Hand Count	2
Functions	Central hours; central minutes
Hacking Seconds?	No
Country of Manufacture	Switzerland, Swiss made
Known Models	(Add your watch to the comments below…)

The Frederic Piguet caliber 21 is a vintage 2-hander mechanical watch movement. With a height of just 1.73mm, the cal. 21 is what Frederic Piguet officially describes as ultra-flat. The development of this movement dates back to circa 1925.

This movement is sometimes referred to as FP 21 (or FP21), it also serves as the base for many other calibers.

There is also a skeletonized version of the caliber 21 known as “21P”.

Watch Brands Using the FP21 Ebauche:

Brands that use the FP-21 as a base movement include:

• Patek Philippe 175
• Patek Philippe 177
• Rolex 650
• IWC 171
• Omega 700
• Longines 310
• Certina 20-10
• Zenith 53.5
• MING FP21.M1

Other brands that used the FP-21, but didn’t appear to use their own caliber number:

• Piaget
• Blancpain
• Cartier
• Movado
• Bueche Girod
• Ebel
• Bucherer

Sometimes these movements will feature a boxed 21 engraving.

Some others designed calibers based on the FP-21:

• Audemars Piguet 2003
• Piaget 9P
• Vacheron Constantin 1003
• Jaeger Le Coultre (JLC) 803

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