Norditropin by Novo Nordisk pens are convenient and easy to use. They come premixed and need to be kept refrigerated before use. Just take the cap off the pen, screw on a Novofine needle, dial in your dosage and then inject.  Norditropin is our best seller and happens to be the most popular brand in the world. After first use the pen can be kept out of the fridge if the temperature is below 77 Ferenheight.