OCUKAC2318 Hydraulic Pattern Changer Valve for John Deere Tractor Excavator. PC Series pattern changer spool valve is designed to switch joystick functionality on equipment such as excavators. When operators move from one machine to another, they can set-up the joystick controls to function in a familiar format. Carbon steel with trivalent plating. Fitted with Nitrile seals. Operated by turning the handle 90 degrees to change the joystick pattern. Reduction in training time when switching between machines made by different manufacturers. Simple, reliable operations with no electronic components. Quick and easy to install. Operating temperatures (With Nitrile seals): -40°C (-40°F) to 106°C (223°F). Switching joystick functionality between machines made by different manufacturers.