The PetSafe ScoopFree Sensitive Crystal Cat Litter Tray is a completely disposable tray that works with the PetSafe ScoopFree Self-Cleaning Cat Litter Box. With disposable trays, you don?t have to see, touch or smell messy waste. Simply replace the disposable tray every few weeks, and your ScoopFree cat litter box is just like new. Each tray is pre-filled with Sensitive Crystals cat litter that's free of perfumes and dyes and reduces odor better than traditional clay or clumping litter. Low-tracking and odor-reducing crystal litter keeps your home litter-free and smelling great.