For those interested in the sterile Sub-Date, Exp II and GMT IIs, here the info from the supplier on the movements:
<< 机芯是广州明珠机芯。
3针SUB手表是明珠2813机芯
4针GMT手表是明珠3804机芯
明珠2813和3804比海欧机芯更稳定。>>
Simple Translation: Not Swiss or Japanese, just Chinese Automatic movements.
Basic specifications is the same for the all four models:
MOVEMENT: Automatic (Sub-date) / GMT Automatic (Exp IIs & GMT II)
CASE DIAMETER: 40 mm without crown
THICKNESS: 13 mm
DATE: Quick-Set Date
GMT Hand: Can be set separately by turning the other way from the date set
DIAL COLOR: Black dial (Exp II, Sub-dt, GMT II) / White dial (Exp II)
CASE MATERIAL: Polished 316L Stainless Steel case with brushed back
Bezel: Ceramic (Sub-dt & GMT II) / Stainless Steel for Exp IIs
BRACELET: Stainless Steel
FRONT GLASS: Sapphire Glass
BACK: Solid Stainless Steel case back
Hackable: Yes