1" Male NPT plastic yoke, compatible with the plastic bypasses used on the following filter/softener control valves:

• WaterSoft Isobar 1 & 2 (red knobs)
• CSI Signature 1 & 2 (red knobs)
• Cygna (red knobs)
• Most residential Fleck models (5600, 2510, 9100, etc)