For mommies who ordered the pump from USA, you will need to buy an adapter/tranformer here for the local voltage.
There are 2 ways in which you can do it. If you go to those DIY hardware shop, you can get a transformer for about $16. But for this, you will need to piggyback the original USA adapter onto this transformer, so it's pretty bulky and heavy.
Otherwise, you can go Sim Lim to purchase an adapter ($38) that fits directly with the pump, so you don't need to use the USA adapter at all. I find this method much better since it is much lighter.