I've read a ton of bad stuff about the emery cat, from trouble with ordering (the way it works you end up ordering twice as much as you wanted) customer service is hard to pin down when trying to get the order problem straightened out....to...the sandpaper is only sprayed on the tops of the cardboard "cells", which renders it useless for the purpose they claim, and worse; cats having their claws ripped out when using it.
Steer clear is my advice.
