The Alternance 10 or A-10 is an automatic watch movement from Soprod.
Introduced in 2004, the A-10 was intended as a drop-in replacement for the ETA 2892. As such, it shares most of its key dimensions with that movement, including a diameter of 25.6 mm and height of 3.6 mm. Like the 2892, the A-10 is a three-hand movement with a quickset date wheel.
Around the same time, Seiko Instruments introduced their 4L family of movements which shares many obvious similarities to the A-10. Neither company has admitted which direction the technology flowed when developing these movements, but insiders suggest that Seiko was responsible for the basic design. When Peace Mark of Hong Kong purchased Soprod in 2007, Seiko reportedly cut off contact with the company but continued to produce their 4L movements for another five years.
The A-10 remains in production and has been used by many Swiss manufacturers. It is certified Swiss Made, and Soprod offers a large number of customizations to it, from power reserve indicators to moon phase dials to chronograph modules. Soprod offers the A-10 in three versions Basic, “open heart”, and skeleton.