BD Ultra-Fine Short Insulin Pen Needles 8mm x 31G are coated with special Micro-Bonded lubrication for a more comfortable injection. This Insulin Pen Needle provides reliable injections for all patients with no pinch-up of skin required. The Ultra Fine Short Insulin Pen Needle is thinner and more delicate for less pain and greater comfort. These Penta Point Needles are long enough to pass through the skin into the fat layer but short enough that it does not reach the muscle.