Drawcords bottom hem with dual barrel stoppers. 7.37 oz, 250 gsm (US), 12.3 oz/Lyd (CA), 100% polyester double knit. – Factory Direct Pricing. White T-shirts are Dyed. Just like every other shirt, but the White dye is the most abundant and cheapest available, because face it cotton is mostly white to start with, so is does not take much to change it.