The Pentek ST-2 is the correct system that uses:
The Pentek ST-2 Stainless Steel Filter Housing is ideal for high pressure or hot water applications that are not durable enough for plastic filter housings. Located at the bottom of the stainless steel sump is either a pipe plug or pet-cock for draining. Also known as part number 156018-02, this housing system provides heavy-duty filtration used for smaller water filtration systems and point-of-use (POU) applications. The heads are manufactured from nickel-plated cast-brass.
Pentek ST-2 Stainless Steel Water Filter Housing Specifications:
Do not use the Pentek ST-2 Filter Housing with water that is microbiologically unsafe or of unknown quality for drinking water applications. The maximum cartridge diameter is 3" (76mm). This filtration housing will not accept GAC, CC, CGAC, TSGAC, WS, PCF or PCC Series Cartridges.