Ropes used in tourism, mountaineering, and caving are made of nylon (polyamide), as this material provides high strength, wear resistance, and the necessary elongation. The basic structure is standard—a kernmantle construction (a core with a sheath) compliant with DSTU 3402-96—though the specific composition of the core and sheath can vary significantly depending on the rope's intended properties (such as flexibility, strength, and elongation).                    There are also specific standards for ropes used for human belaying: static ropes – DSTU EN 1891:2006, which prohibits ropes with diameters of less than 8.5 mm or more than 16 mm, and mandates a minimum strength of 18 kN for Group B and 22 kN for Group A; dynamic ropes – EN 892 standard.