Measure before ordering and use the instructions on the individual product page. Different products sit on different parts of the body, so one measurement cannot be reused for every collar or harness.
Flat collars
Measure around the neck where the collar will normally sit. Choose a size whose stated adjustment range contains that measurement. Do not size down outside the listed range.
Canny head collar
Measure the neck snugly and high behind the ears. Do not use the normal collar measurement and do not add two-finger space. The product page lists the exact 9–23 inch size ranges and the maker’s boundary guidance.
Harnesses
Measure the widest part of the chest just behind the front legs while the dog is standing. Weight-based sizes are a starting point only. Adjust every strap, check that movement is not restricted, and confirm all buckles are locked before attaching a leash.
Beds and mats
Measure your dog in its usual resting position and compare that footprint with the product’s open dimensions. Also measure the crate, vehicle seat, or floor space where the item will be used.
Vehicle covers
Measure the seat width and depth and compare the locations of headrests and seat-belt openings with the product details. A seat cover is not a vehicle restraint.
If a listing does not provide enough information to choose confidently, email parkandhound@gmail.com before ordering.