I bought this before the size/price options came into play so got quite a bargain on the large piece for my obsy monitor. However, even at the full price for a large screen, this is worthwhile. Many monitors do not allow much backlight reduction, so even when you select a red screen, it is bright (not dim) red and compromises night vision. Using the filter means you lose much less night vision. I added some velcro pads so it could be easily pulled off for normal computer use.
