Compatibility:Compatible with eufy Breast Pump E10 / E20 / S1 / S1 Pro. Prevents Leaks from the Top: Features a spill-proof valve to help prevent messy spills and keep things clean. Safety First: Made from food-grade silicone, the spout cap that comes into contact with breast milk ensures safety and gives you peace of mind about your baby's milk. Guaranteed Reliability: eufy breast pump accessories are covered by a 90-day limited manufacturer's warranty. Lifespan: Typically lasts 3 months. Replace if suction and performance decrease with use and sterilization, or based on your usage.