· SILICONE MATERIAL: Made from high-quality silicone, Medela spare nipples are neutral in taste and odor· CLEAN & SANITIZE: The nipples are dishwasher-safe (top rack only), and they can be sanitized using Medela’s Quick Clean Microwave Bag· COMPATIBLE WITH THE MEDELA BOTTLES: Designed to fit with all Medela bottles· FLEXIBLE FLOW OPTIONS: Available in two flow sizes (sold separately) – Slow Flow (S) and Medium Flow (M)