I purchased the unit from porchpotty.com I got the standard, which has the drain hose and I rinse it at night after Reg's last potty. If you want to go the artificial grass way but not spend that kind of money, my friend bought a piece of artificial turf from Home Depot and trained her Maltese to use that. The piece she purchased is about the same size as the Standard Porch Potty that I have and Coop uses it daily. I did order her the little fire hydrant to put on it for Coop to aim at
It might also help if you have a friends dog come over to use it as well, Reg and Coop seem to be in competition to cover each others scent at both here and at my friend house.