The breast flange is the funnel shaped piece that fits on your breast over your nipple and areola. A good fit is important! It can help make breast pumping comfortable and help you pump more milk. 
Ameda® HygieniKit® Milk Collection Systems come with a standard size 25.0mm flange, but we also offer a range of different flange sizes and inserts – our CustomFit Flange System – to ensure you find your best fit.
 
The Reducing Insert reduces the standard 25mm flange to 22.5mm.
 
This item is sold as a single, so you will likely need to purchase 2.