NRS Breastcollar Conector StrapBiothaneBrownStainless Steel HardwareNRS-BCSNRS Biothane Breastcollar Conector Strap, NRS-BCS The NRS Tack, Biothane Series consists of extremely long lasting biothane tack that is the perfect choice for dependable tack that will hold up for years of use. Biothane is sweat and rot resistant keeping the tack pliable.