Hi @Thin_Lizzy do you mean humulin insulin? It has a number of different types: short , long and intermediate acting. I'm on the short acting (T1 on a pump).
If you look at your insulin cartridge or prescription it should specify what type of humulin you are on. It would help if you told us.
Tagging @Lakeslover who is an experienced insulin using T2
Is there something specific you wanted to know about it. (As a T1, I'm a big fan of insulin, though not of hypos.)