Each EasyTouch pen needle cap is color-coded for easy and accurate identification; confusion is reduced significantly by allowing insulin-injectors to quickly identify their correct gauge and needle length: This insulin pen needle is 31 gauge and has a yellow cap.. Easy-to-read information on each side of the box. Needles are made with surgical steel.. Triple-bevel cut for a sharper point.. Thin wall cannulae for easier flow. Electro-polished to remove burrs for a smoother injection. Film coated for maximum comfort. 5/16 inch length. Stainless steel. Disposable. Hub connecting type: pen connection.