My truck is a 2000 model and the top windows use two gas struts on each window. I replaced them in 2010 and it's time to do it again in 2020. I assume they will last until 2030. Easy replacement and a lot less than a new topper or truck. This truck costs about $0.21 per mile to run, excluding fuel, insurance and license. Included purchase price, routine maintenance, servicing, tires and parts. Drives like new!