The Nuliie Flange Sizing Kit is a set of BPA-free silicone flange inserts designed for nursing mothers and breastfeeding support. The kit includes flange inserts in sizes 13/15/17/19/21mm, suitable for 24mm shields, and is made from food-grade silicone material. The clear-white flange sizing kit is lightweight, skin-friendly, and easy to clean, making it a convenient accessory for electric breast pumps. The product dimensions are 5.24 x 4.57 x 2.8 inches, weighing 0.63 ounces, and is manufactured by the brand Nuliie.