The new sterile 60ml ozone-compatible syringe comes with a custom-made silicone plunger. When standard plastic syringes with rubber plungers are reused multiple times, the rubber plunger will expand, which creates more rubbing and friction on the sidewall, as well as strong odors. Since the plunger in the 60ml syringe is made from silicone, it won't wear down as quickly as rubber does when in contact with ozone.