Longines Caliber L893.5 Watch Movement

Brand	Longines
Caliber Number	L893.5
In-House?	No
Base Caliber	ETA A31.501, A31501
Movement Type	Automatic, self-winding mechanical
Lignes	11.5”’
Diameter	25.6mm
Height	4.6mm
Jewel Count	26
Beat Rate	25,200 vph, 3.5 Hz
Lift Angle	Unconfirmed
Power Reserve	64 or 72 hours (see below)
Rotor Style	Ball-bearing
Hand-Windable?	Yes
Anti-Shock Device	Incabloc
Silicon Balance Spring?	Yes
Hand Count	3
Functions	Central hours; central minutes; small seconds subdial at 6:00
Hacking Seconds?	Yes
Country of Manufacture	Switzerland, Swiss made
Known Models	Longines Master Collection (Ref: L2.843.4.63.2, L2.843.4.93.2, L2.843.4.73.2), Longines Heritage Classic (Ref: L2.828.4.73.0, L2.828.4.73.2, L2.828.4.53.2, L2.828.4.53.6) (Add your watch to the comments below…)

The Longines caliber L893 is an automatic watch movement with a small seconds indicator. This movement is based on the ETA caliber A31.501 (which itself is a Swatch Group-only caliber based on the ETA 2892A2) and is equipped with a silicon balance spring for increased resistance to magenetism.

This calibre is found in the Longines Heritage Classic model, but unfortunately, Longines is one of those brands that creates caliber confusion by not providing more transparency with regards to movements on their product pages. The official Longines site simply refers to this caliber as “L893”.

It doesn’t help that models (the Longines Heritage Classic for example) has a solid caseback. If you were to open the watch (of have a model with an exhibition caseback, such as the 2024 Master Collection model), you would find a trailing variation indicator in the caliber number engraved on the rotor: L893.5.

Power Reserve:

You may see this movement listed by other watch publications as having a power reserve of 64 hours. That is partially true. For example, when Longines introduced the L893.5 powered Heritage Classic Tuxedo dial (Ref: L2.660.4.93.0), they listed it as having a power reserve of 64 hours. Fast forward to the July 2023 announcement of the L893.5 powered Master Collection line-up and Longines officially states that the power reserve is up to 72 hours.

Therefore, power reserve will depend on which model you have.

It is Caliber Corner’s position that when a brand makes a dramatic improvement or upgrade that affects the specs of a movement, then a new caliber number, or at the very least a new variation indicator, should be used to prevent caliber confusion.

Note: Longines also states that if your watch is out of power reserve, you should wind it about 30 times to get it going again. They do not disclose how many winds of the crown will give the watch full power reserve.