First all silicone straw cup that holds its shape! GoSili cups are 100% European grade silicone with an embedded stainless steel ring to hold its shape. It won't collapse when gripped. GoSili's patented technology paves the way for a new drinking experience and is the perfect alternative to plastic to-go cups. Dishwasher and microwave safe. Easy to use, easy to clean, easy to GoSili. Microwave safe. Dishwasher safe. 16 oz silicone cup. Fits in all cup holders for on the go. 100% silicone. Durable drinkware. Light weight straw cups. Fun and trendy.