Insulin Pen Needle Color Code Purple Gauge 31 Gauge HCPCS A4215 (Disclaimer) Hub Connecting Type Pen Connection Hub Material Polypropylene Length 5 mm Needle Material Surgical Steel Safety Feature Without Safety Sterility Sterile Type Mini UNSPSC Code 42142523 Usage Disposable Wall Type Thin Wall Coated with special Micro-Bonded lubrication for a more comfortable injection Lilly and Novo insulin pens and dosers