Medical Items And Instrument Like Needles, Tweezers Material Barrel Material: medical and high transparent PP with Plunger stopped ring. Standard: 1ml 2ml 2.5ml 3ml 5ml 10ml 20ml 30ml 50ml 60ml Plunger Material: medical environment-protect and natural rubber. Standard piston: Made of natural rubber with two retaining ringsOr Latex Free. Piston: Made of Synthetic non-cytotoxic rubber, free from The protein of the natural latex to avoid possible allergy.