Review on Bottle Narrow Opening Adapter Leak Proof by Lance Foster

Bought to replace the cover I originally had with a black ring on a white washer. Based on other reviews I wasn't the only one. I sterilized it but still decided to replace it with a new cap. Works great as a cap, closes tightly, easy to open. Nice big loop for hanging your finger. To be honest I kept the old bottle capped for days. I will be actively keeping it open more often to try and prevent this black ring from forming.