This is a new counter top design, can't use it for undersink installation. Sharing the same 3M NSF certified C Complete cartridge as in AP Easy Complete.
If you want cheaper option and undersink installation, go for the RM350 3M CTM-01. After one year usage, replace the cartridge with C Complete. You will get same water quality as in CTM-02.

wah , buy cartridge refill price vs buy cartridge + head adapter why $$ diff so much?

This is a new counter top design, can't use it for undersink installation. Sharing the same 3M NSF certified C Complete cartridge as in AP Easy Complete.
If you want cheaper option and undersink installation, go for the RM350 3M CTM-01. After one year usage, replace the cartridge with C Complete. You will get same water quality as in CTM-02.

Yes, but you need to remove the filter head from the CTM-01 housing because C-complete cartridge is longer than C-CTM-01 cartridge.

If you want cheaper way, just buy the AP2 filter head from Taobao.  Use this keyword: 3M AP2 机頭 to search.

Yes, but you need to remove the filter head from the CTM-01 housing because C-complete cartridge is longer than C-CTM-01 cartridge.

If you want cheaper way, just buy the AP2 filter head from Taobao.  Use this keyword: 3M AP2 机頭 to search.

Replace what head ? You have only one head which you take out from the ctm-01 plastic housing.
Yes easy to remove, just tear out the plastic housing.
C-complete is the replacement cartridge without head. You just need to replace the ctm-01 cartridge with c-complete cartridge.

Both c-ctm-01 and c-complete is compatible to AP2 filter head as per picture below:

Basically it clarifies that eSpring is indeed a NSF certified product but the scamming part is the over pricing product for a simple PP+carbon block + uv water filter.

Thanks for the link, I found the product code in China for 3M filters.
With these infos, it helps to search for cheaper replacement 3M cartridges in Taobao. For example, I can save more than RM100 for C-Complete replacement cartridge.
https://world.taobao.com/item/528935850182....0.pVvyCK#detail

To those who are looking for budget but branded PoE filter under Rm300, grab this 3M at Giant before end of this month.
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Yes but you need to remove the plastic housing because c complete is bigger.

Yes but don't use ceramic as pre filter. Use pleated polyester instead.
Being kiasu and kiasi, I have 2-stage pre filter before my Culligan EZ4 carbon block. 1st stage 5 micron pleated polyester for sediment and 2nd stage Fresca Disruptor for bacteria/viruses. I bought it from bro hestati.