which unit should i get ?

i plan to get a unit to be used in Singapore and i went to Sewatec.de and saw a lot of different countries like UK, Australia .

Could some one advice please ?

In general the units are all the same. Only difference is the power supply.
There are a lot of different power outlets around the world, so you should chose the one who´s suitable for your country.

As I know, in Singapur the UK plugs are used.

Have look at https://aquariumcomputer.com/en-GB/p...-uk-pab-detail
If the sockets are like yours, UK is the right decision.