Adjustable straps on the neck and chest determine whether the clothes will slide. So the most important data is neck and bust
Neck : Neck girth is where the the fixing place of the strap, please measure the lower postion of neck girth
Bust : Please measure the girth behind the front legs
Back length : Because the jacket do not cover the entire neck, the back length is measured from the bottom of the neck to the hips.
After you determine the bust and neck circumference, the raincoat will most likely not slip.
However, due to the different body types of dog breeds, raincoats may not be able to cover longer dog breeds completely, please understand.