I had ours made at a local upholstery shop using heavy tarp material, app. 3' x 5' with grommets on the corners & midpoints, edges doubled
up & sewn. We use bungees to tie them on, ok if it's an excavator with cab guarding, forestry cabs with lexan are a pain, nothing to tie to. I
think they cost maybe $80-$100 each actually pretty cheap when compared to replacing windows, NOBODY makes a flat window anymore. If
you're hauling off highway much even if the window survives without tarping it's usually so muddy the operators are generally less than
impressed.