The mud does not come in on the dog. It comes in on four paws that walk the whole length of your hallway before you catch up with a towel.

This is a cup lined with soft bristles. A little water in the bottom, paw in, twist, and the bristles work between the pads, which is where the dirt is and where a towel has never once reached. The paw comes out before it touches the floor.

The mat by the door fails differently. A mat is passive, and a dog on its way somewhere gives it one flat step per paw. It also keeps what it takes off. The cup reverses that: you hold it, one paw at a time, and you empty it in the sink. Empty it every time. Water left standing in there is not a cleaning tool by the next walk.

It cleans a paw, not a leg. A dog that went through a puddle up to the elbow is not a paw problem, and this does not reach it.

Size matters here more than anything else about it. Measure the paw, not the dog. A cup that is too narrow turns every use into a wrestling match and it will end up in a cupboard. The medium suits most dogs, but most is not all. The 4.4 stars across 25,219 ratings say it works in a lot of houses and nothing about yours. Before you order, pick up a back foot and see whether your dog lets you hold it.

It has to live by the door you actually come in through. That sounds like a throwaway detail and it is the whole product, because a cleaning tool you have to go and fetch is a cleaning tool you stop using by week three. If two doors are in real use, buy two.