if you travel often, then you should really consider buying this! its a wifi device and can connect up to 8 devices!
the battery lasts for around 12 hours and its really small and portable. you can visit the webpage a.pokefi(whilst connected to its wifi) to view the data usage and to top up the data. the device comes with 5gb no expiration data and it lasted me for a good 3 months.
subsequent top ups are at usd15 for 5gb(if my memory serves me well) but i think they have an expiration date.
can be used in all countries SIA flys to, except for NZ and Dubai.
pro tip: you can buy it on board if you're travelling with Cathay. i heard that it's much cheaper!