Use this for the flange of my pump as I’m struggling to get consistent pumps and found it was a suitable for me. This is made from a soft silicon like material it’s flexible and gentle so it doesn’t hurt when used it’s easy to take in and out and sterilise which hasn’t affected the quality it still looks brand-new. It doesn’t need any instructions for assembly as it’s very straightforward and although it’s very simple and design it has made a big difference in me getting milk pumped out.