This is the exempt catalyst for the UC22 Kosmic Acrylic Urethane Clearcoat. It’s used at a 4:1:1 mix ratio (clear : catalyst : RU series reducer). As with all House of Kolor catalysts, it’s intended for use with House of Kolor paints only — due to their unique chemistry, House of Kolor catalyst should never be substituted with other brands. Note: this item is not for sale in California due to VOC regulations, and orders placed in VOC-restricted states are typically cancelled.