Discard the housing it will be similar to 3M C-Complete undersink filter (around Rm800 to RM900).
Once 3M CTM-01 (RM299) due for cartridge replacement, replace it with NSF/ANSI Standard 42 & 53 certified 3M C-Complete cardtrige. Can withstand constant water pressure undersink because both C-CTM-01 and C-Complete cartridges are designed for undersink and countertop installation.
I'm using NSF/ANSI standard certified 3M easy complete filter undersink installation currently. Drink directly from the tap.

Yes, both sharing the same filter head but you need to remove the CTM-01 housing in order to fit in c-complete cartridge because c-complete cartridge is bigger.