What is insulin pen?

Insulin pen is a kind of pen device that is as thick and thin as the blood collection pen of blood glucose meter and the needle tube for injection. You can change the "refill" to insulin refill.
The insulin pen is very convenient to use. There is a scale on it, which shows how many units of insulin are injected at a glance.
The injection needle is very thin, like the thickness of hair. Therefore, the injection does not hurt at all.
Insulin pen can be safely carried, whether by plane or train.
Remember, the pen with insulin refill can only be kept for one week at normal temperature. Too long will affect the quality of insulin in the pen.