The Opti-Flecs 9411 Quarter CTO LED Filter is a color correction filter used to convert daylight 5600K to tungsten 4500K. A moderate warming gel improves the quality of LED lighting and helps to match to existing lighting. Excellent addition to an LED key light or back light. Improves skin tones when using daylight LED fixtures. Sheet size of 11.81" x 11.81" fits most 1x1 LED light fixtures including LitePanels 1x1 and LitePanels Astra. Filter can be cut and trimmed with matte knife or scissors for a pefect fit with other size lights. Great for color correcting architectural LED lights. The semi-rigid panel can be used without a color frame in most instances. Thickness: 10 - 13 mil. Designed for use with low heat LED lights only.