Scale of Protection: 5 (see FAQs for more detail) The DEFENDER is a 4 inch cut collar that consists of a 6 layer construction: 3 layers of 1,000 denier Cordura nylon, 2 layers of 1000 Ballistic nylon, and the final layer is the nylon straps. Even with all these layers, it maintains an amazing level of flexibility! The Defender cut collar offers 100% stainless steel hardware. All DEFENDER cut collars come standard with tracking collar loops, reflective tape, d-ring, two buckles and Velcro closure. The DEFENDER cut collar is flexible enough to run on any bay dog and durable enough for the toughest of catch dogs! The DEFENDER is the ultimate in cut collar design! These are the neck sizes the collars will fit: Small = 14"-21" Medium = 16"-22" Large = 18"-24"