Longines Caliber L888.4

Brand	ETA
Caliber Number	A31.L11, A31L11
In-House?	No
Base Caliber	ETA A31.L11
Movement Type	Automatic
COSC?	Yes
Lignes	11 1/2”’
Diameter	25.6mm
Height	3.85mm
Jewels	21
Power Reserve	~72 hours
Lift Angle	51 degrees (unconfirmed!)
Vibrations Per Hour	25,200, 3.5Hz
Shock System	Nivashock
Balance Spring	Silicium (silicon)
Rotor	Ball bearing system
Winding Direction	Bi-directional
Hacking?	Yes
Hand-Windable?	Yes
Hand-Count	3
Features	Central hours; central minutes; central sweeping seconds; date at 3:00 (no date available)
Country of Manufacture	Switzerland, Swiss made
Known Models	Longines Spirit (ref: L3.810.4.73.6, L3.811.4.53.0, L3.810.4.73.2,  (Add your watch in the comments below…)

The Longines caliber L888.4 is 3-hand automatic watch movement based on the ETA caliber A31.L11. It is a Swiss made with 21 jewels, produced by ETA (Swatch Group).

Caliber L888.4 VS L888:

There is a similar caliber L888 (without the .4). Both movements are based on the ETA A31.L11, with the main difference between the two being that the L888.4 is a Certified Chronometer (COSC) with a silicon balance spring). Watches with the .4 will likely have “Chronometer” printed across the dial (Longines Spirit example), while the L888 may simply read “Automatic” or nothing at all (Longines Legend Diver example).

Silicon Balance-Spring:

As mentioned above, one of the Longines caliber L888.4’s notable features is its use of a silicon balance-spring (hairspring). With so many magnets being used in modern everyday accessories and appliances, magnetism is one of the most common threats to the accuracy and functionality of a watch. Using silicon for the balance-spring makes it antimagnetic. As Longines puts it:

“Silicon is lightweight material which is resistant to corrosion and it unaffected by normal temperature variations, magnetic fields, and atmospheric pressure. Its unique properties enhance a watch’s accuracy and longevity.” –source

To reinforce the importance of magnetic resistance in a watch and its impact on a timepiece’s overall performance, Longines has extended their manufacturer’s warranty to 5 years on all watches with a silicon balance-spring (announced 9/2020 – source).

Power Reserve:

Longines has quoted two different power reserve figures for the L888.4: 64 hours (here) and ~72 hours (here). This could be a mistake on their part, but the best way to get an idea of what to expect is for the community to share power reserve experiences in the comments below.

No Date Version:

There is also a time only version of the L888.4 without a calendar complication. The No Date (ND) is still a COSC with all of the same specs, just no date at 3:00. This version can be found in the Spirit references L3.810.1.53.6, L3.810.1.53.2, L3.811.1.53.2, and L3.811.1.53.6.

Examples of watches with this movement:

Additional Resources:

• View more Longines calibers
• ETA caliber 2892-A2