They are hoop snares. They are made from high tensile wire,the snare wire is tied to a leg using a half hitch knot same knot as you would use on a fence,push the legs down either side of the run then set snare at the right height. They are ideal for use on soft or sandy soil,the high tensile wire takes the strain of the rabbit in the snare,the rabbits usually wrap themselves round one of the legs and die pretty quick