Insulflex (with an L between insu and flex) is standard fare. Don't get Insulon or Superlon as they are nowhere as near in performance. Some places do sell K-flex (Italian) which is also better but pricier.

Commonly many models of 2.0 copper piping internal diameter utilize 1/4"(6.25mm) liquid and 1/2" (12.5mm) gas.

Not all models utilize this size for the rated cooling capacity HP ie some manufacturer's models can use larger than typically found e.g. Sharp 1.5HP uses 2.0HP pipes of others. Others even could be smaller than the typical e.g. Daikin 2.5HP can be drop in upgrade for other 2.0HP as their gas pipe internal diameter is 1/2" (12.5mm).

If you like, upgrade piping to one size bigger ie 2.5HP which commonly utilise 1/4" (6.25mm)  liquid and 5/8" (15.8mm) gas. This way you can still use 2HP then upsize to 2.5HP next time. Some like the Daikin runs 3.0HP on this common 2.5HP pipe diameter esp the FTKV70.

Useful note: copper pipes connecting the compressor and FCU can be bigger than spec but never smaller. Always follow manufacturer drain hose size. For new I would always go for 19mm (3/4") internal diameter. Typically some use 5/8" (15.8mm) but larger ones have better clog free assurance.

Ok. Sounds like you're based very near SG ie JB. I would like to know also where to source for Armacell's products like Arma flex if you're actually based in Klang Valley. Should go for 1/2" or even 3/4" insulation thickness for the outside and 1/2" or 3/8" thickness inside the FCU. Be sure it's encased in white trunking to protect it on the outside from the elements also until the last part where it's exposed to reach the compressor. Hope it goes well and if you can let us know how it went and feasts our eyes with pictures.

Update: see the pictures in this blog as to the extent taken to insulate even outdoors with trunking casing.