Watts-SF-40 Watts String Wound Cartridge Standard 40" in R-Can Sterilight (S740RL-HO) UV Replacement Lamp Bulb for SP740-HO or ceramic pre-filtration

or ceramic pre-filtration

Engineered by Global Water to match G4CT specifications for flow rate

so plan for slightly more clearance below your sink deck than a non-air-gap model would require

Dual resin ion exchange

Watts-SF-40 Watts String Wound Cartridge Standard 40" in R-Can Sterilight (S740RL-HO) UV Replacement Lamp Bulb for SP740-HO or ceramic pre-filtrationWatts Premium Filtration Watts SF 40 String Wound Sediment Cartridge 40 Inch Industrial length polypropylene string wound filter for whole house and commercial applications requiring extended sediment capacity 100% Polypropylene Food Grade 40" Length WHY IT WORKS String wound construction for heavy sediment loads Precision Wound Design Polypropylene string wound tightly around a core creates gradient density filtrationouter layers catch larger