The AR20890 Unloader Valve is a bolt on Regulating Valve from AR Annovi- Reverberi.
This is the AR Mini-Matic 4/B Series Unloader valve for RC, XT and XM Series AR Annovi-Reverberi high pressure pumps.
The AR20890 Unloader Valve comes with the following standard features:
Fits RC, XT,XTA, XM, XMV,XMA, SXMA, XTV Series Pumps
Max PSI: 2600
Inlet Port: 1/2" Female
Outlet Port: 3/8" Male
Max GPM: 3gpm
By-Pass: Aluminum Built In By-Pass 91540510
Injector: Adjustable 2.0
Brass Inlet Mounting Bolt AR2260420
Brass High Pressure Outlet Bolt AR1540270
The Mini-Matic 4/B Bolt on unloader was used and various models or pressure washers throughout the industry and can be found on most major brands of pressure washers.
You can also tell if you have a Mini-Matic Unloader valve by looking at the brass by-pass adaptor this brass piece will have MINIMATIC stamped into the brass housing.