I bought a used aluminum one a few years ago because I take mine off during the summer since I use the pickup bed for other uses and the kennels get plenty of air circulation during the warm times when the topper is off. the biggest issue I’ve come across is trying to keep it “air tight”, I’ve sealed the tailgate best I could but it still gets dusty. air vents/windows with screens is needed for ventilation, also having the side windows being able to open up is a must IMO. I had a truck with a topper that did not have windows that opened, that was a PITA to move and grab stuff in the back, might as well of had a SUV at that point.