The size really depends on your pet.  If the dog is large or tall like a greyhound or great dane, a much larger unit is recommended. 

To determine the proper size, measure from the ground to the top of your dog's shoulder, this is called the wither height.  Now subtract 6 inches for extra large to medium dogs or 4 inches for smaller animals.  The result will be the recommended model height for your dog.  You can now go to the chart and determine which is the most suitable size for your pet. The chart size and model you choose determines just the price range. When you order, we ask for your dogs actual measurements and then tailor the unit to your dog's actual height.

Now go to Our Products to find your choices.