Would not recommend
There's no instructions and I wasn't sure where and how should I fit this awkwardly designed filter. Finally I've found a demo on YouTube and I've used adhesive spot and stick blue plastic cover inside my cats litter box.
Unfortunately my kitten worked out how to open it after first use ... he opened a bag with filtering granules and spread it all over the floor! I wasn't in a room at the time so you can only imagine my shock when I've noticed brownish granuless/powder all over thinking my kitten had a diarrhoea. Luckily my kitten opened only 1 of 2 bags. I've placed the other one on top of hooded litter tray, where a scoop is and I can tell filter works good and that's the only reason I'm giving this product 2 stars.