Use once, destroy and contain. 1/2cc for 50 units or less. 1/2 inch (12.7 mm) length needle. Worldwide leader in insulin delivery devices. Sterile single use syringes. Control Number 5021161. Choose the right BD insulin syringe size for you! Needle Gauge: The higher the number, the thinner the needle. Do you prefer to have a thinner needle or a thicker one that is less flexible. This syringe has a 30 gauge needle. The higher the gauge, the thinner the needle or a thicker one that is less flexible. This syringe has a 30 gauge needle. The higher the gauge, the thinner the needle. Needle Length: Speak with your health care professional to find out what needle length is best for you. This needle is 1/2 in (12.7 mm) long.