This must be what you are talking about:
“Supports Struvite Dissolution
Supports urinary health
Increases urine volume to help decrease struvite and calcium oxalate levels
Royal Canin Urinary SO Index® promotes a urinary environment unfavorable to the development of both struvite and calcium oxalate crystals
100% Complete and Balanced Nutrition
100% Satisfaction Guaranteed
Canine Urinary SO Small Dog is a complete and balanced diet specifically designed for small breed adult dogs. It is formulated to aid in the nutritional management of calcium oxalate and struvite urolithiasis.”
– See more at: https://www.royalcanin.com/products/royal-canin-veterinary-diet-canine-urinary-so-small-dog-dry-dog-food-8.8-lb-bag/488488#sthash.XwQ2ioGa.dpuf
