Tommee Tippee Closer to Nature Advanced Comfort Medium Flow Teats The award winning closer to nature teat from Tommee Tippee is designed to mimic the natural flex, feel and movement of mum's breast, to make switching between breast & bottle easier than ever before. These advanced comfort teats cannot be used with the standard closer to nature(R) bottles. They can only be used with closer to nature(R) advanced comfort(TM) or anti-colic+ bottles. Teat care and maintenance:- it is highly recommended that you replace your teats at least every 2 months or at first signs of wear and tearTeats available in medium (3months+) and fast flow (6months+).