Herm Sprenger prong collar in Curogan metal Great condition, only used for about one week 2.25MM link thickness Comes with 3 additional Curogan Herm Sprenger links Prong collar should fit neck size up to 14” and each additional link is 1.0625” long With the additional 3 links, the prong collar should fit up neck size up to 17” (approximately) Plus optional plastic nubs to put over prongs (see last image) Curogan metal is less likely to stain white fur than chrome or other metals. It can be used with dogs with sensitivities to other metals