The NovoLog Penfill, recognized as NovoRapid in Canada, serves as an insulin pen cartridge. Each cartridge holds a 3 ml solution, amounting to 300 units. Specifically, every ml offers 100 units of insulin aspart, equivalent to 3.5 mg. When ordering, ensure you’re selecting the right cartridges, as several insulin brands, including Levemir, have their cartridge varieties.