These aluminum syringes are made to be used over and over. The Cap-Chur charge is inserted behind the rubber piston within the syringe, and it explodes on impact and drives the piston forward forcing the liquid out through the needle. Available in numerous sizes and needle combinations for many applications. It is sometimes advisable to replace the rubber plunger (#33915) portion of the syringe when it begins to harden, typically after 3-4 uses.