Plush Pet Loo Grass is specific material and fit replacement grass for: The Pet Loo Large "Original" (size 33"x33" or 83x83cm) The Pet Loo Medium "Mini Wee" (size 24"x24" or 63x63cm) The Pet Loo Small "Kitty Kat" (size 17"x21" or 53x45cm) There are many varying types of synthetic grass on the market. The Synthetic grass used for The Pet Loo is of optimum quality designed and developed specifically to reduce your hassles. After lengthy testing, we have ensured that the grass guarantees maximum drainage. The grass only needs to be replaced if you feel it's necessary. CLEANING TIPS:Daily: Pour warm water over the grass to flush out any excess urine.2-3 times a Week: Spray WEE Care or Kitty Care on The Pet Loo and grass. Let dry.Weekly: Thoroughly spray The Pet Loo with WEE Care or Kitty Care and leave for 5-10 minutes. Remove the grass and wash down the entire unit with midpressured water – (Ideally a hose or in the shower until liquid is clear).Air Out/Dry: Please ensure that the grass is dried thoroughly after washing.