The size on the snap-in glazing is 1/2 inch for the flat bottom piece by 1/2 inch for the curved part. The flat piece fits under the glass and there is a very tiny ridge just before you get to part that curves up. That tiny ridge "locks" the glazing into the frame.
Of course these are aluminum windows, but there is also what looks to be a small metal glazing point securing the glass as well, so that you do not have to remove the windows to change the snap-in glazing.
The current snap-in is a cream or light almond color to match the vinyl siding. I suppose if I am re-glazing all the windows the color could be white.
