The ETACHRON Regulator

The ETACHRON regulating system (and similar designs) use rotating "blocks" attached to the hairspring stud and a movable regulating arm. The regulator effectively shortens or lengthens the hairspring and can be rotated to maintain perfect contact with the spring. Similar systems are employed by many watches, some of which use other regulating and indexing systems.

ETACHRON has officially been available in four versions:

With a pointer on the balance cock
With an eccentric screw corrector on the balance cock
With the Valjoux corrector on the balance cock
With no pointer or screw corrector

This has lead to some confusion, with some sources claiming that only the movable stud and rotating block is "ETACHRON", since these are present on all such movements. But ETA documents are clear that all of these components are part of the ETACHRON system.

24 Hour Hand
Chronograph
-2-Button
-Cam Switching Chronograph
-Column Wheel Chronograph
--6-Column Chronograph
-Modular Chronograph
-Monopusher Chronograph
Date
-Bi-Directional Date Correction
-Big Date
--Double Concentric Wheel Big Date
--Overlapping Concentric Big Date
-Date by Pointer
-Instant Date Change
-Quick Date Correction
-Retrograde Date
-Semi-Instantaneous Date Change
Day
-Bilingual Day Wheel
-Day by Pointer
-Instant Day Change
-Outer Day Wheel
-Quick Day Correction
-Retrograde Day
GMT Hand
-Independently-Adjustable 24 Hour Hand
Hacking Seconds
Hand Winding
Modular
Month
-Month by Pointer
Moon Phase
Power Reserve Indicator
Regulator
World Time

12 Hour Chronograph Hand at 6:00
24 Hour Hand at 10:30
24 Hour Hand at 9:00
30 Minute Chronograph Hand at 12:00
30 Minute Chronograph Hand at 3:00
30 Minute Chronograph Hand at 9:00
Big Date at 3:00
Central 24 Hour Hand
Central 60 Second Chronograph Hand
Central Date Pointer
Central Hour Hand
Central Minute Hand
Central Power Reserve Pointer
Central Seconds Hand
Central World Time Disc
City Window at 3:00
Date Pointer at 3:00
Date Pointer at 6:00
Date Window at 3:00
Date Window at 4:30
Day Pointer at 3:00
Day Pointer at 9:00
Day Window at 11:30
Day Window at 12:00
Day Window at 3:00
Hour Hand at 12:00
Hour Hand at 3:00
Hour Window at 12:00
Hunter Small Seconds Hand
Lépine Small Seconds Hand
Month Pointer at 12:00
Month Window at 12:30
Moon Phase Wheel at 6:00
Open Heart at 6:00
Open Heart at 9:00
Power Reserve Pointer at 6:00
Power Reserve Pointer at 7:00
Power Reserve Pointer at 9:00
Power Reserve Pointer at 9:30
Small Seconds Hand at 3:00
Small Seconds Hand at 6:00
Small Seconds Hand at 9:00

	Complications	Hands
Brand	Winding	Regulators
Production Periods	Frequency	Anti-Shock
Jewels	Balance Mount	Back-Side Features