I HAVE BEEN VISITING THIS SIGHT CALLED PROSNARE.COM AND THESE ARE HEAVY DUTY LOOPS, ONCE IT CLOSES, LIKE THE COYOTE STARTS THE PULL AND IT TIGHTENS AROUND ITS NECK, DOES IT LOCK AND NOT MAKE THE LOOP ANY BIGGER, LIKE CAN IT ONLY GET SMALL AND NOT BIGGER?

If it is a non-relaxing snare it will tighten and not relax. The loop will tighten tighter the harder the animal pulls. Relaxing snares are mainly used in areas of high pet populations, when non-target animals may be caught, and are designed to relax and keep the animal alive.