The first filter has the following filter setup.
1st Stage 5 micron 10" high-capacity polypropylene sediment filter --removes dust, particles, and rust.
2nd Stage Carbon Block 5 micron 10" --removes chlorine, odor, organic contaminants, pesticides, and cysts.
3rd Stage FDA (Dow Chemical) 100 GPD TFC reverse osmosis membrane --reduces 93% to 98% of Total Dissolved Solids most chemicals, metals, bacteria, viruses and other contaminants.
4th Stage Preliminary Inline Filter - Reduces chemicals, chlorine, improves taste, odor and improved clarity.
5th Stage 10" KDF/GAC Pre-Filter Cartridge for increased purification
6th Stage Secondary Inline Filter - Additional filtration to remove sediments, improve taste and make water clearer at point of use
Multiple carbon filters and only as small ad 5 micron. I would suggest a 1 micron sediment filter before the RO
membrane and realisticly any carbon blocks after the RO
membrane is useless or ineffective since the water comming out of the RO
membrane will be 99.9% pure.
FIlter two looks to be the same as filter 1 execpt it has a prefilter pump added to boost water pressure. Unless you know your home water pressure is low the pump is un needed.
The last one you linked appears to be false advertising becaues it says 100GPD in the title and in the text of the ad but the description of the membrane says different