The refreshing drink or local Chinese cocktail at Chinese coffee shops is known as Kat Chye Shin Mui. It is yellow lime or Calamondin with preserved sour and salty plums. I found it a bit too salty and ordered another without the sugar and salt coated dried plums. There was only one solitary dried plum in the drink, anyway.
Asam Boi is a local drink with preserved plums (shin mui) floating in it. The dried plums from China are salted, sugar coated and sourish although the drink may also have tamarind and/or limau kasturi (calamansi) added for stronger colour and flavour. It is a refreshing, tangy, cold drink on a hot afternoon.
Besides Hainan White Coffee, Yik Mun also serves Limau Asam Boi at RM 4.50. Quite expensive, I know.
Panasonic Lumix GM-1, ISO 200, f5.6, 1/400 sec.