Compatible with the testo 549, 550, 557, and 570. With 4 port manifolds (testo 557, 570), two Valve Replacement Kits may be required.
Includes: 2 Knobs, 1 Blue Knob Insert, 1 Red Knob Insert, 2 Locking Pins, 2 Valve Seal and Cup, 2 Valve Nut and Stem