This is the only lot I have like this. All still in their very old packages. 3 packs are size 6 which say 1/2 mass each (1 mass = 1200). The other 3 packs are size 8 which are 15 dtz. I assume that’s “dozen” which would be 180 beads per pack. I think the size is in mm but I showed a mm ruler next to them too.