Martingale dog collars, the latest trend in dog training, are designed for dogs with a neck thicker than their head. The problem with a regular dog collar on a dog with a thicker neck is that the dog can back his head out of the collar. Martingale dog collars are designed to fit a dog's neck snugly yet comfortably. A Martingale dog collar can be made in three easy steps using materials from your local hardware store.
First, measure your dog's neck and head. When finished, the Martingale collar will need to be able to slide over the dog's head, and the "control loop" will pull the collar snugly around the neck. Cut the nylon webbing to 1½ inches beyond the neck measurement. You will also need an additional strip of nylon webbing for the control loop; it can be about half the length of the first strip.
Now, run the additional strip of nylon webbing (for the control loop) through both sliders and sew the D ring to the strip. You can use any extra fabric you may have to cover the bottom of this area so the D ring blends into the collar, or you can cinch together an inch or so of the strip to cover the bottom of the D ring. Now you have created your control loop. It should look something like a circle with a large ring (D ring) and 2 sliders on either side. (A variation on this would be to use a slider on one side and a buckle on the other if you want the option of taking the collar on and off without sliding it on and off.)
Take the nylon webbing that you measured around your dog's head and neck, and slide one end into each slider. Wrap the nylon webbing around the slider and sew, making an "X" with the thread.
The nylon webbing can be thin or thick, depending on the look you want. Bigger dogs may look better in a thicker collar, and smaller dogs in a slender collar. If you wish, decorate your nylon webbing with rhinestones, beads, bows or puffy paints. The control loop will tighten the collar when you are training or walking your dog and the dog begins to pull. At other times, the Martingale collar should sit comfortably on the dog's neck.
Be sure to always check the tightness of the collar around the dog's neck. When the collar is not being used for training purposes, you should be able to fit two fingers in between the collar and the dog's neck.