The Regular Size EZ Fill Roll ‘n Clean Self Cleaning Litter box is quick And easy to use, and makes filling a breeze with the new Easy Fill Hood. The Roll ‘n Clean features a patented sifting Grate that separates clumps from clean litter and deposits The waste into the pull out drawer. Simply roll the litter box All the way onto it’s top and back again and the litter box does the rest of the work separating clean litter from the waste!