http://armdevices.net/2014/01/27/sub-90-android-smartwatch-by-shenzhen-zhengfang/600mAh battery, uses a single-core MediaTek processor (not sure which one), price is below $90 depeding on the bulk purchase quantity, they have 200 people in their Shenzhen factory.
"It's not dual core, but you can put tf card inside to enlarge the memory"
Cellphone watch 3G (sim card inside)
Waterproof
3 days standby battery life
most important spec less than 90 USD in quantities for 100pcs, apparently it's reference price? I guess that means retailers can sell it for 90$?
When some manufacturers put out smart watches to only extend the functionality of smartphones, shouldn't fully featured smart watches be extended with some kind of tablet device to have bigger screen?