Use the Spectra Breast Shield Set to replace your original breast pump parts or to keep an extra set at work. If double pumping, please buy two. The Spectra Breast Shield set is great for our Spectra S1 Plus, S2 Plus, S3 Pro, or 9 Plus breast pumps. 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. <br><br> Owned and operated by fellow moms, lactation consultants, and registered nurses, Spectra is committed to supporting every mother on the beautiful journey of breastfeeding. From our unique Natural Nursing Technology to our one-of-a-kind customer care, you can count on Spectra to be right there with you, every step of the way. We are moms. We are nurses. We understand.