Get inside the factory of ICS Airsoft in Taiwan in this video by Airsoftology. You'll get to see that is a big building when an aerial shot was taken at the beginning of the video which Jonathan Higgs confirms. As for its location in Taiwan, it is in Taichung City, which is south of Taipei, and the western part of the island.

Take a look inside PolarStar Airsoft's factory as Airsoftology gives a guided tour... "Ever wanted to know how the 100% USA made Polarstar products are made? Well, Jonathan walks you through their factory to show you the entire process in just under 4 mins... plus stay to the end for a sneak peek of their latest innovation!"