Plastic Slush Cups Medium 12.oz 330mlPlastic Slush Cups Medium 12. oz 330ml Our high quality clear plastic 12. oz 330ml Medium size cups are very popular for slush. There are 1000 cups in a case. We use one size of domed lid, with a hole for the straw. This one size domed lids fits all three sizes of our plastic cups. So you don't need to buy all different size lids. This keeps things simple.