Anti-Slip O-Ring is a standard wide neck size, to reduce slippage/leaking between parts.
This tiny little part may well be one of our favorites! These days, it's totally normal to be fitting different parts from different brands together, and the fit isn't always perfect. If you've ever had a bottle unscrew from a breast shield, you'll know what an awful feeling it is!
Our Anti-Slip O-ring is made out of soft silicone and you use it with standard wide neck parts to keep things more secure. Use it between wide neck breast shields and bottles, our Pump2Bag clips, or with our narrow to wide neck adaptor.
All Pumpables parts in contact with your milk are free from BPA, phthalates, and other nasties.