- Our signature collar stiffeners. - Comes in a set of six custom made bones. - Measuring 2 1/8" to fit perfectly in any of our collars - Bend them a bit for a rounded collar look or keep them straight for a more traditional look. Our signature collar stiffeners. Comes in a set of six custom made bones. Measuring 2 1/8" to fit perfectly in any of our collars. Bend them a bit for a rounded collar look or keep them straight for a more traditional look.