generated in arresting a fall without creating forces high enough to injure the climber. Such ropes are of kernmantle construction, as described below. Conversely, "static" ropes have minimal stretch and are not designed to arrest free falls. They are used in caving, rappelling, rescue applications, and industries such as window washing. The UIAA, in concert with the CEN, sets climbing-rope standards and oversees testing. Any rope bearing a GUIANA or CE certification tag is suitable for climbing. Climbing ropes cut easily when under load. Keeping them away from sharp rock edges is imperative. Previous falls arrested by a rope, damage to its sheath, and contamination by dirt or solvents all weaken a rope and can render it unsuitable for further sport use. Rock climbing ropes are designated as suitable for single, double or twin use. A single rope is the most common, and is intended to be used by itself. These range in thickness from roughly . Smaller diameter ropes are lighter, but wear out faster. Double ropes are thinner than single, usually and under, and are intended for use in pairs. These offer a greater margin of safety against cutting, since it is unlikely that both ropes will be cut, but complicate both belaying and leading. Double ropes may be clipped into alternating pieces of protection, allowing each to stay straighter and reduce both individual and total rope drag. Twin ropes are thin ropes which must be clipped into the same piece of protection, in effect being treated as a single strand. This adds security in situations where a rope may get cut. However new lighter-weight ropes with greater safety have virtually replaced this type of rope. The butterfly and alpine coils are methods of coiling a rope for carrying. Gallery of µCT/micro-CT images and animations 2D images / sections 2D flight-throughs/sections 3D renderings 3D flight-throughs/sections Handling Rope made from hemp, cotton or nylon is generally stored in a cool dry place for proper storage. To prevent kinking it is usually coiled. To prevent fraying or unravelling, the ends of a rope are bound with twine (whipping), tape, or heat shrink tubing. The ends of plastic fibre ropes are often melted and fused solid; however, the rope and knotting expert Geoffrey Budworth warns against this practice thus: Sealing rope ends this way is lazy and dangerous. A tugboat operator once sliced the palm of his hand open down to