Method Seven Catalyst HPS 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 cameras. Made from aircraft-grade high-temperature injected polymer for durability.