Know Your Needles A Quick Nursing Guide! , Today, lets understand the different types of needles and their clinical purposes , Green Needle (21G) For IM injections like vaccines or B12 Injection Kit: Syringes & Needles & Alcohol Wipes Medbasic Needle Sizes Explained: Choosing the Right Gauge for Different Injections Injecting B12 Enhance Me Training Academy Syringe Sizes KMED B12 vitamin Store Needle and Syringe Information for injecting vitamin B12 and vitamin C. Find out what needle sizes are recommended.