Emergency Relay Valve, Suitable for pre-121 trailers, converter dollies or exempt trailers. Has automatic bleed down feature. FOR USE IN AIR HYDRAULIC SYSTEMS ONLY - DO NOT USE THEM TO CONTROL SPRING BRAKES,3/8"-18 auxiliary reservoir port on bottom of valve drilled and tapped for use in air hydraulic systems. Do not use them to control spring brakes.
Repair Kit use part number :RN10HL