Made from 100% high-quality, food-grade stainless steel (#304), these sippy cups are durable, lightweight and BPA-free.  They do not leach harmful chemicals, toxins or flavours into the liquid.  Along with Avent's BPA-free sippy cup spout (made of polypropolene #5), they are a safe choice from top to bottom.  Can be cleaned in the dishwasher, or with warm soapy water.