M size Used it for a 6kg Toy Poodle. The M size might be too big for smaller dogs. It catches the poop, so it doesn't get tangled in the paws or fur, making cleanup very convenient. I've used it for almost a month. I hand-washed it after soaking it in OxiClean, but please refrain from purchasing if you are concerned, as it was hand-washed by an amateur. The fibers attached to the Velcro are from the diaper. The stains in the second and third photos were made when soaking in OxiClean. They are on the belly, so they are not very noticeable, but please refrain from purchasing if you are concerned. I was using cost-effective adult incontinence pads, so I will include a few. - Color: Navy - Material: Combination of mesh and fabric - Design: T-shaped design - Fasteners: Snap buttons and Velcro Thank you for looking.