I have back to office already. If you use the Avent manual pump, I think you have to buy the biggest size of "fridge-to-go" - 6 cans one.
Must be very careful when cleaning the Avent pump in the office, I have lost the little cover "circle" part on the 1st day. It's lucky that there is a spare part!!! Just worries if I lose the spare part again, can I only buy it from the store...