The Watts 10" replacement cartridge bundle includes all of the filters you need to keep your Watts Quick-Twist 50 GPD Four-Stage Reverse Osmosis System working properly for a full year. This bundle includes two sediment pre-filters, two carbon block pre-filters, one GAC carbon post-filter and one RO membrane. The sediment and carbon block pre-filters should be changed every 6-12 months, the GAC carbon post-filter should be changed every 12 months and the RO membrane should be changed every 24 months. 

• Includes (2) 10” WQTSC-10 Sediment Pre-Filters
• Includes (2) 10” WQTCBC-10 Carbon Block Pre-Filters
• Includes (1) 10” WQTCGAC-10 GAC Post-Filter
• Includes (1) 10” WQTCM50-10 RO Membrane 

NOTE: This item qualifies for free shipping within the 48 contiguous United States.