The Midland Haldex KN28042 is a four-port, single control line relay valve used to apply and release service brakes on tractors and trailers. The supply (port 2) and delivery (port 4) connections are both 1/2-inch; the control (port 1) inlet is 1/4-inch. Crack pressure is 4.6 PSI. The valve cover can be rotated 360 degrees without affecting performance, making installation easier in tight brake system layouts. This multi-application valve crosses to several OEM numbers including N30100JA, N30100JB, N30100JC, N30100JD, and N30100JE. Bracket is not included. Repair kit RN10HK is available separately. A genuine Midland Haldex part from Pro Gear and Transmission. Call us to confirm fit for your specific tractor or trailer application.A factory handling fee of $25.00 per unit is added at checkout.FeaturesFour-port, single control line relay valveSupply (port 2) and delivery (port 4): 1/2-inch connectionsControl (port 1): 1/4-inch connectionCrack pressure: 4.6 PSIRotatable cover for flexible installation – no effect on performanceCrosses to OEM numbers N30100JA, N30100JB, N30100JC, N30100JD, N30100JE; bracket not includedTech SpecsSupply (Port 2): 1/2″Delivery (Port 4): 1/2″Control (Port 1): 1/4″Crack Pressure: 4.6 PSIOEM Part Number: N30100JDBracket: Not includedAdditional InformationKN28042 crosses to OEM numbers N30100JA, N30100JB, N30100JC, N30100JD, and N30100JE. Brackets are available separately. Valve includes bushings and plugs to match OEM production valves. Repair kit: order part number RN10HK separately.