Just a quick note to people. Avoid these. They are a total con. I purchased 5 of these during the Prime event, unfortunately the prime event advertising wasn't anywhere near as clear as the normal £4.99 price adverts. I thought great Idea..... when I run out of cat litter, press the button and more is ordered. Nope. You can only select one of three very eclectic and expensive products from the range, starting a £3.75 per litter box change. The real horror starts when you try to send them back.... you can't. You have to call customer services, kick up a fuss to try and get your money back.. Real snake oil these things.......