BD PEN NEEDLE 31G 8MMBD Pen Needle 31G 8mm is a medical device used primarily with insulin pens for subcutaneous injection of insulin or other medications. Uses of BD Pen Needle 31G 8mm: Insulin Administration: Used by diabetic patients to inject insulin under the skin. Other Injectable Medications: Suitable for growth hormones, GLP 1 agonists, and other injectable treatments prescribed in pen form. Convenient & Hygienic Delivery: Sterile, single use needle that ensures