These are the TRUEplus syringes, 31G 0.5CC 5/16In. This syringe will hold up to 50 units. This is a shorter style needle being that it is 5/16 inch. For your comfort, these feature a silicone coated needle with a precision-cut, tri-beveled needle tip. Use once and discard of in an appropriate container for sharps. Please keep out of the reach of children.