The BESTfit Charge Air Cooler 29 x 30.75 In. with a 4 In. Core is an aftermarket cooler designed to fit Kenworth T660 (2008-2013) and Kenworth W900L/AeroCab (2008-2016) models, providing a durable replacement. Built to original equipment specifications, this cooler features a heavy-duty core measuring 29 inches in height, 30.75 inches in width and 2.75 inches thick, with 4-inch inlet and outlet connections that match common OE piping standards. It is tested to be 100 % leak-free and is intended to replace a wide range of OEM part numbers, including several F31-608810 and F31-608811 variants as well as N4106001 and W4715001 series numbers, helping ensure correct application when OE numbers and dimensions are verified before purchase. Buyers can choose to order the cooler sold individually or as part of a complete kit that includes four heavy-duty clamps, two red 4-inch silicone hoses and a set of mount bushings to simplify installation