Stainless steel adapters are durable, resist solvents and are very easy to clean. It is available in 5 sizes: 3oz (90mL), 6.8oz (200mL), 13.5oz (400mL), 22oz (650mL) and 28oz (850mL). If you're mixing on a scale, use the "max fill" notation on each cup to fit the maximum amount.