Quanta will be the sole manufacturer of the second-generation Apple Watch, according to a few sources out of the China supply chain.
The same sources believe that the manufacturing company will ramp up mass production on the "Apple Watch 2" sometime in the second quarter of 2016, following reports that it began a trial production on the smartwatch this month.

The reason for Quanta's status as the only Apple Watch 2 manufacturer stems from rumors surrounding Apple's predicted low-volume production output for the second-generation wearable device.
Citing "weaker than expected shipments" of the first Apple Watch, the supply chain sources point to the company's tempered production forecast for its next version of the wrist-worn device.