Typical!
As soon as I mention that I've never seen milk in bags, guess what! About an hour later, I'm in a supermarket and spot this.
纯牛奶 (chún niú nǎi) = pure cow's milk. I'm not sure if it's the milk or the cow that is pure! Whichever, it doesn't come in multi-litre packs. 180g = 186.3 ml.
In my defence, I'm not a milk drinker, so maybe it was always there , but I didn't notice. I only ever use milk to make yoghurt and then I buy it in 1 litre cartons. I'm not sure what I'll do with this amount.