Hemp Martingale Dog Collars-L(18_26)-RED Hemp Martingale Dog Collars. Our non-slip Martingale Star Dog Hemp Dog Collars feature triple layer 100% hemp canvas construction; contoured martingale closure and the most distinctive quality trimming available. When the dog tries to pull their head out of the collar the tension on the leash pulls the small martingale loop taunt which makes the large loop smaller and tighter on the neck - preventing escape. When adjusted properly the dog is never choked but the collar stays snug ge&lt;/b&gt;: Width 1 in. Fits 18 to 26 inches.