4 installed on my 2016 Tacoma. Fronts fit well with 3 factory screw holes. The back fits into the factory screw holes, but lacks that support on the inside edge. I didn't like the look of the flaps, but I needed something as I had a 200 mile dirt trail planned. After I put them on, they stay. For example, it looks a lot better than the factory hardflaps and it goes well with the off-road truck.