Knotty Girlz 4 Knot Horse Rope Training Halter - 3/16" (5mm) VERY THIN! Stiff Polyester Halter 3/16" ROPE IS VERY THIN! If you want a standard 4 knot halter, check out our 1/4" stiff 4 knot halters: Amazon search: KGH-4K-8TF Knot on pressure points for training horses. No hardware to break. This polyester halter rope holds up well in adverse weather conditions with great abrasion resistant properties. Stiff rope makes it easy for halter to hold its form and more reactive to horses. Used by many famous trainers throughout the world. Strong rope with little stretch. Halter with additional knots on the nose for added pressure. Manufactured by the Knotty Girlz, manufacture to the trainers.