1、GET THE RIGHT FLARE SIZE: The flare size of the breast pump is crucial in breastfeeding. The improper flared size will reduce the comfort and efficiency of the mother breast pumping. This nipple ruler will help you quickly determine the right nipple cover to give you a better breastfeeding experience 2、SOFT AND SAFE MATERIAL: Nipple ruler is made of excellent silicone material, odorless and non toxic, light weight and elastic. Unlike fragile plastic with incisive edges, this nipple ruler is soft and bendable without stinging the skin 3、ACCURATE AND QUICK MEASUREMENTS: Using a scale on the edge or by placing the nipple into a suitable hole, the nipple ruler provides accurate measurements, including 21 nipple measurement holes, from 10mm to 30mm, and is easy to read 4、SIZE ADJUSTMENT: Based on the elasticity of your nipples, you may need to go down a size if your nipples are elastic, or up a size if your nipples are less elastic. If you feel uncomfortable or experience a continuous reduction in volume, you may need to try a different size 5、PERFECT GIFT: A must have gift to new mothers so they can find the right flannels and enjoy breastfeeding Item Type: Flange Measurement Tool Rectangle Size: Approx. 18 x 10 x 0.3cm / 7.1 x 3.9 x 0.1in Round Size: Approx. 11.6 x 11.6 x 0.3cm / 4.6 x 4.6 x 0.1in Material: Silicone 2 x Silicone Measuring Stick 2 x Measuring Stick