This is a new Mack Charge Air Cooler. This charge air cooler has the connections with the standard slip on 4" hose connections. This fits Mack and Western Star models R & U for the years 1983 to 1991. Please confirm your Model R or Model U. The core size is 30 7/16" x 25 1/4" x 2 5/8". Check your OEM number before placing your order. Or call us with any questions before ordering.