Method Seven Catalyst LED Phone FilterMethod Seven Catalyst LED Phone and Tablet Camera Filter Create professional quality media in your grow room with the Catalyst Phone Clip Photo Filter. The Catalyst clips securely to your cell phone or tablet, balancing the color spectrum with a high quality Carl Zeiss lens for insane optical clarity when used under HPS (High Pressure Sodium) lights. The filter screw mount is a 37mm aluminum alloy ring and can be removed and adapted for security