According to the principle of sterility, syringe needles, pistons, nipples, needles must be kept sterile.
The syringe consists of a needle and a syringe, wherein the needle comprises a needle tip, a needle stem, a needle plug, and the syringe comprises a nipple, an empty cylinder, a piston, a piston shaft and a piston handle.
The commonly used specifications are 2 ml, 5 ml, 10 ml or 20 ml syringes, occasionally 50 ml or 100 ml, and intradermal injection with 1 ml syringe.