I've kept coming across some products that list drill bit sizes in mm. I was happy to finally fit the set in the ranges I normally need and with all the sizes in between it's great to have more options than just the basic 2,3,4,5,6 sizes. Haven't used them for heavy work yet, but they're great for modeling where I use them. I wish they came with a storage box but I was able to make my own which worked great.