Yaay, thank you for your response, ChristieHi Michelle, you’ll be just fine using 6mm in the pen cartridges. I’ve used both, although with Lev pens, but both 8mm and 6mm work in drawing out the insulin. You probably know this already, but don’t inject air into the pens like you do with the vials. Pump the syringe like usual but have it at zero, then draw out the insulin![]()