Sizing guide included in the product images.

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. Compatible with all Medela, Lansinoh, and Hygia pumps. BPA free. Food Grade. Includes one pair. Please see FAQ section on the BabyMotion Page for using with other pumps and email contact@lacteck.com for additional questions.

4th Gen improvements over 3rd Gen: softer and more comfortable design and material. 12mm, 15mm, and 18mm are packaged differently due to inventory shortage.