Thought I'd take a stab in the dark and see if anyone here has found a local supplier for GE household water filters. Or an overseas supplier that ships to Thailand at reasonable cost. These can be bought in the US for $10 or less. Crap brand equivalent filters here are probably double the price and of unknown quality.

The specific filter I'm looking for is the one pictured below (FXUTC). It will be used as a pre-filter to extend the life of my purifier filter. I'm currently using a 5 micron pre-filter but thought I'd upgrade to this one which is 0.5 - 1 micron at only a slightly higher cost.

I must say my bowels have never been more consistently 'regular' since I installed the purifier. Before this I only bought top brand drinking water like Nestle, Sprinkle etc. Not only am I saving money in the long run but am getting much cleaner water.

That looks like a somewhat-standard filter cartridge that can be found a DIY stores (HomePro, HomeWorks, Watsadu, etc) or even larger Tesco shops. I'm talking various brands, but not GE.

Be alert to the size, though. Take an old one with you if possible. There are two variations, and one is .5mm taller than the other, and of course I bought the taller one and it leaked a tiny bit no matter how tight I screwed on the cover.