Proper flange fit essential for optimal pump performance. The Evenflo AdvancedFitTM Flange System includes two larger flange sizes, providing mom with different options to allow for a more comfortable pumping experience. The Extra large (33 millimeter) and Double extra large (36 millimeter) flanges work with all Evenflo Advanced Double Electric Breast Pumps. The Evenflo AdvancedFit Flange System Features: * AdvancedFitTM flange system includes 2 different sizes for ideal comfort; * Works with Evenflo Advanced Double Electric Breast Pump; * Proper flange fit essential for optimal pump performance; * Includes video guidance on proper flange fit; Evenflo has partnered with Shari Criso, a leading breastfeeding expert and lactation consultant, bringing you quality education to help you achieve success. It is our goal to not only provide you with dependable, quality products, but also ensure you have the resources you need to have a positive and successful breastfeeding and pumping experience. For video guidance on proper flange fit, visit: www.PerfectFlangeFit.com For nearly a century, Evenflo has been a worldwide leader in the development of innovative infant care and juvenile products. Their award-winning, innovative products enhance parenting experiences and baby's development, earning families' trust as they care for their newest and most precious family members. Shop Evenflo strollers, car seats, play yards, safety gates and more in our Evenflo Brand Store!Evenflo Feeding