With the personal fit flex breast shield you can easily adapt the way your breast shield fits to help you find the most comfortable, most efficient position to pump, even as your breast shape changes. at a glance: 105 degree celecius angle improves fit for better milk flow the oval shape can be rotated 360° soft, smooth, flexible rim four tunnel sizes available: 21mm, 24mm, 27mm, 30mm our "breast shield fitting flyer" guide will help you find the right one for you made from bpa-free materials features : • it's a whole new pumping experience, personalized for mum. • its available in 4 different sizes for maximum comfort and pumping efficiency - 21mm, 24mm, 27mm and 30mm. • the rim of the breast shield is made with a soft, natural-feeling material that lays smoothly on the breast for comfort.