The small box is 28" x 11" and the small stilt tops are 1.75" square. Most toy and the smaller terrier breeds match this size box.

The large box is 36" long and 16" wide. The large stilt tops are 3" square.   The Large box is suited for most working,  herding and sporting dogs, along with some of the bigger terriers.

The extra large box is 40" long and 17" wide. The extra large stilt tops are 4" square. It suits Irish Wolfhounds, Saint Bernards, Great Pyranese, and Great Danes.

CHOOSING THE CORRECT SIZE

When choosing the correct size box and stilt(s) for your dog(s), draw the dimensions on a large piece of paper. i use a newspaper. it is plenty big enough , even for the extra large box. Lay the paper on the ground. Mark the outside dimensions of the boxes, 40", 36" or 28" on the paper. Bring your biggest dog over to the paper and have them stand on the drawing. Choose the size box you will need for your dog or breed.

You will do the same thing with the stilt sizes. Draw the dimensions on the paper and again bring your biggest dog to the drawing. 4",3",2 1/4" and 1 3/4" When choosing the stilt size , remember to always get the size that fully fits the dogs foot. You don't want too big and you certainly don't want too small.

Ideally you want a stilt that just fits the foot with nothing left over. Too big and they dance around putting two feet on one stilt. Too small and the dog feels insecure. However, you must error on the side of too big if the dogs foot is an inbetween size. Often you will need two sizes of stilts to accomadate different ages of dogs and/or breeds.