Use the Spectra 28mm Breast Shield Set to replace your original breast pump parts or to keep an extra set at work. If double pumping, please buy two. Spectra 28mm Breast Shield set is great for our spectra pumps when needing replacement parts in a set. Spectra rmends 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, 9 Plus pumps. The Spectra 28mm Breast Shield Set includes 1 Wide Neck Breast Shield, 1 Backflow Protector, 1 Duckbill Valve, and 1 Tube. Gender: unisex.