CONTROL YOUR END DUMP TRAILER AND WALKING FLOOR OR END DUMP AND SIDE DUMP TRAILER FROM THE SEAT OF YOUR TRUCK WITH THIS PNEUMATIC VALVE PACKAGE. THIS VALVE FEATURES ONE SINGLE ACTING SPOOL WITH AN ADJUSTABLE WORK PORT RELIEF FROM 1750-2200 PSI TO RUN AN END DUMP TRAILER AND 1 DUAL ACTING SPOOL WITH A SYSTEM RELIEF ADJUSTABLE FROM 2200 PSI - 3000 PSI TO RUN A WALKING FLOOR TRAILER, A SIDE DUMP TRAILER, A BELT TRAILER OR ANY TRAILER THAT NEEDS A DUAL ACTING SPOOL. DUAL TRAILER SETUP AIR/HYDRAULIC VALVE, PRESSURE PORT: #12 SAE O-RING, TANK PORT: #12 SAE O-RING, A & B PORT: #10 SAE O-RING, AIR CONNECTION: 1/4" POLY TUBE, FLOW RATE: 20 GPM, INTEGRATED SYSTEM RELIEF: 3000 PSI MAXIMUM. ** AIR TUBING AND TOGGLE SWITCH SOLD SEPARATELY