I purchased this on Amazon in October as a replacement because I lost the original, but I found it, so it's been stored unused. The box is dented from Amazon's shipping. ↓Excerpt from Amazon Breast Pump All Models Silicone Cap + Silicone Valve This is a set of silicone cap and silicone valves for breast pumps. For when you lose them, etc. Compatible with all Pigeon Breast Assist breast pump models. Material/Ingredients/Raw Materials: Silicone rubber Set contents: Silicone cap (1 piece), Silicone valve (3 pieces) Sterilization/Disinfection methods: Boiling/Steam: ○ Microwave: ○ Chemical solution: ○ Heat resistance: 140°C