The size varies from 8-10mm in an irregularly wonderful way. These potato pearl beads are all drilled with a 2.5mm hole that will easily fit a 2mm cord... Perhaps a nice leather cord or a bunch of different textured ribbons. The hole diameter of these large holed freshwater pearls are very consistent which is important when planning your jewelry designs. The design possibilities are endless with these beauties. Each strand is 8 inches with approximately 24 pearls per strand.