Calling all members of the itty bitty nippy committee! Girl we been there, and we're still there. Use these detachable flange inserts to fit in your breast pump better: Which means you can pump out more boobie juice for baby! Breast pumps are one size fits all, yet not all of our titty twisters are. That's why moms need a flange insert to help reduce the nipple tunnel so we can extract more liquid gold during every pump! Washable, reusable, and BPA-free silicone. Compatible with almost all major brands! Don't skip out on the flange inserts, and milk your utters in the most efficient way possible! 17,19, 21mm inserts for use with 24mm detachable shields 24mm inserts for use with detachable 27mm shields Insert for use with 24 or 27mm breast pump detachable shields. It will reduce the nipple tunnel to 17/19/21 or 24mm.