Use the Spectra Premium Accessory KIT to replace your original breast pump parts or to keep an extra set at work. Spectra 24mm Breast Shield Accessory KIT is great for our spectra pumps when needing replacement parts in a set. Spectra recommends replacing your parts every 3-6 months for optimal use. If you are needing a full set of replacement parts or want to have an extra set on hand for home or work this kit is for you and your S2, S1, S9 or M1 pumps. Spectra Baby USA is a top leading breast pump company offering moms the latest innovative breast pumps and supplies. Spectra Baby USA is a team of lactation consultants and pumping mamas that take this journey very seriously. They want to help provide moms all around the world access to a good quality pump to provide breast milk for their babies.