The 2-layer construction of an anti-bacterial dry filter and a strong absorbent and deodorizing mat, so this dog toilet system will not get lost even if you need to replace it for 3 days. The mat should be replaced once every 3 days, and the filter should be changed once a week. Regular is for urine absorption of a dogs weight of 9.8 lbs (4 kg) or less) Remove poop quickly