The Wabco relay valve, part number 4006110320, is a genuine ZF Wabco air system component designed for heavy-duty truck brake circuits. Relay valves are used to reduce brake signal lag on longer air lines, allowing the brake chambers to fill and exhaust faster than a direct signal from the foot valve alone. This part carries an active status and is sold individually (unit pack of one). Pro Gear and Transmission stocks genuine Wabco brake system components for fleet and shop buyers. Call us to confirm this valve fits your specific brake system configuration before ordering.FeaturesGenuine ZF Wabco air system relay valvePart number 4006110320, UPC 193133458951Classified under the Relay marketing group for air brake systemsActive production statusSold individually, one valve per unit pack