An insanely simple device that brews a most delicious cup of tea.
An 85ml gaiwan is extremely useful.
Is an 85 gaiwan too small? Not at all! Many Yixing teapots have very similar capacity, for a reason. Brewing tea in these devices allows you to enjoy tea that can be steeped multiple times. Imagine drinking 10 steeps from a 500ml teapot! A gaiwan like this is quite convenient for gong fu tea service.
The size is quite good too if you're looking to brew a 'full cup' for yourself. Since many teas require just a few seconds (under 10) to steep, you can quickly brew 3 steeps to serve ~ 240ml (8oz).