i had bought the tray at Petsmart....it work great but i just but the UGODOG and i now put newspaper under the grates...which i like better so they don't so happen to step on their mess and its much cleaner since Kioko and MeiLing tend to shred the pee pads...
here is the link to the ugodog...i bought 2 so it was free shipping...i think if you spend over 60 its free shipping..but this was the cheapest i found...hehe
Dog Litter Box | UGODOG® | Indoor Dog Litter Box - MOST POPULAR
and here is the link to the one i bought from Petsmart...hehe
Premium Pad Training Tray - Training Pads - New Puppy Center - PetSmart