Teat: round natural rubber teat 100% free of BPA, PVC and phthalates Made in Denmark. It complies with the strict EN1400 standard. The manufacturer recommends changing the pacifier every 6 weeks We never recommend microwave sterilization. And in this case, as it is a PP pacifier and whose assembly is made with the same rubber as the teat, uncontrolled high temperatures can cause the pacifier to fall apart. We recommend that you heat a pan with boiling water, remove from the stove and place the pacifiers in for 2-5 minutes.