HOW DO I MEASURE MYSELF?
STEP 1: Using a ruler or tape, measure the diameter of your nipple across the middle in millimeters. Do not include the areola.
STEP 2: Based on your nipple diameter, determine your breast shield size according to the diagram. For example, if your nipple measures 25mm, your recommended breast shield size is 30mm. We recommend a larger breast shield diameter than your actual nipple because the vacuum of a breast pump makes the nipple expand.