Typical post lengths range from 6mm to 8mm, and gauge range from 0.8mm to 1.2mm. The right size depends on your piercing location and ear anatomy. At LYANG & CO., we offer flatback earrings in both 18g (1mm) and 16g (1.2mm) gauges, with posts in 6mm and 8mm lengths to suit different ear anatomies and preferences.