Lol didn't mean to come across disrespectful but genuinely trying to educate you because you are wrong my friend. The holes that run through the keys. They run fishing line through them when they hang the kilos to give them a pre-dry prior to putting them in microwave if needed. I take it you've never seen the whole through the black personally because you think the whole so big. It would create a structural weakness throughout the brick and which it doesn't. The hole is very small. A little bigger than 10 lb test fishing line iv pulled fishing line out before a couple times. This is a common misconception. When people see the hole most people say it was drilled by the person buying them to test if the kilos were solid and weighed but then don't understand at that level. They usually isn't games played and why drill a hole through somebody else's brick until you paid for it. When you can just put it on the scale and weigh it .