The LitterMaid Elite Mega Ultimate Edition is an advanced self-cleaning litter box that holds 50% more litter then the competition. This makes it ideal for extra-large cats or multiple cat households. Once the cat leaves the unit, sensors are triggered to turn on the ionizer and timer. After 10 minutes, the cleaning cycle starts and rake moves clumps toward the waste receptacle. The rake opens the waste receptacle cover and deposits clumps before closing cover and returning to the home position. Sealed disposable waste receptacle with carbon filter allows for safe, easy disposal of waste. There is no other Litter box that even comes close to this one and the manufacturer gives this unit a two year warranty to back it up.