I moved into my home last summer, and several windows are missing screens. The windows are less than 20 years old, but my local hardware stores (and several websites) can't get the clips that hold the screen. It is a small plastic clip that is held on one side with the screen beed and the other clips onto the outside window track, picture attached. There are two on the lower half of the window. The upper half of the window has pins that the upper corners of the screen clip into. I would like to replace the screens in those windows, but I can't get the hardware. Does anyone know where to get these or what they are called?