Royal Canin Urinary SO Index® promotes a urinary environment unfavorable to the development of both struvite and calcium oxalate crystals. Urinary SO Moderate calorie helps to maintain ideal weight due to moderate calorie content compared to regular Urinary SO. Relative Super Saturation (RSS) methodology predicts the crystallization of urine. RSS is used to develop diets for cats prone to both struvite and oxalate urolithiasis. Ingredients: Water sufficient for processing, pork by-products, chicken liver, chicken, salmon, corn flour, wheat gluten, modified corn starch, powdered cellulose, natural flavors, glycine, potassium chloride, salt, calcium sulfate, guar gum, taurine, DL-methionine, vitamins [DL-alpha tocopherol acetate (source of vitamin E), thiamine mononitrate (vitamin B1), niacin supplement, biotin, D-calcium pantothenate, riboflavin supplement, pyridoxine hydrochloride (vitamin B6), vitamin B12 supplement, folic acid, vitamin D3 supplement], cysteine, L-carnitine, choline chloride, trace minerals [zinc proteinate, zinc oxide, ferrous sulfate, copper sulfate, manganous oxide, sodium selenite, calcium iodate], marigold extract (Tagetes erecta L.). Morsels in gravy.