They're both from Springwell. That's where the similarity ends. Here's exactly what each one does and which one your well water actually needs.
The CF1 removes chlorine, chloramine, PFAS, and VOCs — city water problems. The WF1 removes iron, manganese, and sulfur — well water problems. They solve different issues. Many well water homeowners run both in series: WF1 first (removes iron/sulfur), then CF1 (polishes chemicals and improves taste).
If you install both CF1 and WF1, the order is: WF1 first, then CF1. Iron and sulfur must be removed before the catalytic carbon stage — iron particles will clog and foul the carbon media if they reach it. The WF1 is always the first system in line for well water.