Insulin Pens

Insulin pens can be helpful if you want the convenience of carrying insulin with you in a discreet way. An insulin pen looks like a pen with a cartridge. Some of these devices use replaceable cartridges of insulin; other pen models are totally disposable. A short, fine needle, similar to the needle on an insulin syringe, is on the tip of the pen. Users turn a dial to select the desired dose of insulin and press a plunger on the end to deliver the insulin just under the skin.

source: http://diabetes.niddk.nih.gov/dm/pubs/insulin/index.htm