Medical Mixed Colour Rubber Stopper For Blood Collection Tube https://www.klstopper.com/product/medical-rubber-products-series/mixed-colour-rubber-stopper-for-blood-collection-tube.html Ultra-low metal dissolution, can be used for human blood metal detection Special surface treatment technology eliminates the effects of silicon treatments on blood products . The most stringent process control ensures the cleanliness of the rubber stopper . Suitable acupuncture resistance，Can withstand 60000 times of acupuncture abrasion