Rainshow'r GK-1 Green Knight Hydroponic Garden Hose Dechlorinator with Hose Saver The GK-1 Green Knight is a non-cartridge garden filter that reduces chloramine compounds. The GK-1 is molded in white UV resistant polypropylene plastic. The Green Knight reduces water flow to 2 GPM to maximize water contact time with filtration media. Enhances plant growth Made in the U.S.A.