This cab insulator set fits Mack CH and CL models and comes as a pack of two. It sits between cab components to cut down on vibration, noise, and heat transfer at the mounting points. No cross-reference numbers are needed since fitment is limited to these Mack platforms.This unit is sold in packs of 2.FeaturesPack of 2 insulatorsCross-references to Mack 20QL259, 20QL259A, 20QL231P4, 20QL289M, 25154049, 20542349Fits all Mack CH ModelsFits all Mack CL ModelsTech SpecsSell pack: 2 piecesCross-reference: Mack 20QL259, 20QL259A, 20QL231P4, 20QL289M, 25154049, 20542349Fitment: All Mack CH Models, All Mack CL ModelsUsed in this Truck Cab modelCooling System Parts & Diagrams