These factories can have multiple parts. Final electronics assembly - the most photogenic stage of operations - tends to be done in clean, well-lit, well-organized, air-conditioned spaces by young women (age 16-20) wearing color-coded paper hats (you don't want aluminum dust or dandruff getting on your circuit boards). But some of the earlier manufacturing stages where you mold plastic or cut metal to make an outer case shell (that is an eventual input to the later process) can be hot and dark and grimy and smelly.