A. We do stock and sell both as we do get requests for them. The main reason people ask for them (in our opinion) is that Home Centers introduced them, and also, it is a very low-priced filter. We don't show them because they are impregnated cellulose cartridge and not good for some situations such as wells with quick pressure changes. Also, there isn't a lot of carbon contact with the W-5 (C1 - W5CIP). We prefer to encourage our customers to use the W30PE or W50PE sediment instead of the W20CL, and the WCC carbon filters instead of the W-5 (C1-W5CIP). The sediment W30/50PE are pleated polyester and much more rugged. The WCC has a lot more carbon contact time. Please note that the WCC is still the large 2 3/4" diameter, while the W-5 is now the 2 3/8" diameter. The WCC will not fit some of the under-counter systems and will not work in systems that use a coupler to connect filters together. Note: W20CL and W20CLA are the same filter.