BabyMotion Flange transforms pumping into nursing by mimicking a baby's suckling motions. It stimulates nipple and areola, increases pumping efficiency, is soft and comfortable. BPA free. Food Grade. Includes one pair for double pumping. Directly compatible with all Medela (except cups), Lansinoh, and Hygia pumps. Please check the FAQs section for how to with other pumps and email contact@lacteck.com for additional questions. 4th Gen improvements over 3rd Gen: softer and more comfortable and discreet design and material. Questions? Leave a comment below!