Measurement method: Maximum size of the collar> Dog head tower> Dog neck tower> Minimum size of the collar. Dog necklace recommended for vocational training, it excellent for controlling and suitable for medium and large dogs, and very fleeting dogs. Not recommended for dogs with respiratory problems. 【Enhanced technology】 Pretty silver color, made of good quality steel, well chromed for strength. Level of polishing mirror, seamless molding, perfect curvature, smooth touch. The surface of the chain is perfectly smoky to avoid hurting the animal. It is non-toxic and harmless for domestic animals, anti-aliaing, anticorrosion, durable and wear-resistant, good cost-effectiveness. 【Durable and resistant】 The chain is welded to argon and Chrome for maximum resistance and durability. And the more durable this necklace thanks to its chain structure, very resistant to bites. The chrome layer makes the necklace waterproof and rust resistant. Attention, do not leave the necklace in the water or