I purchased this in size L, but it was too small for my pet. I think it would fit a size M pet better. I tried it on, so I washed it. The category is for cats, but it can also be used for dogs! Measurements (laid flat): Length from neck to hem: approx. 33cm Neck circumference (straight line): approx. 10cm Chest circumference (straight line): approx. 21cm No stretch