Neat 'n Tidy Litter Sifting Liners make scooping the litter box a thing of the past! Each package contains a one month supply: 28 sifting liners and 2 solid liners. Place liners into empty litter box with the non sifting liners on the bottom. Fill the box with clumping litter (works best with heavier clay litters). To clean the box, simply lift the top liner, sift and toss! Keeps the litter box clean and sanitary, and extends the life of litter by up to 50%!