Flexible (corrugated-black) RKLGF pipes are protective pipes designed to protect electrical wires against mechanical damage (the pipe bends under the influence of force, but does not break) and moisture. Flexible (corrugated-black) RKLGF pipes made of LDPE polyethylene (low density polyethylene) are combustible pipes with good dielectric properties in a fairly wide range of temperatures. Thanks to the extremely low water absorption, their dielectric properties do not change when staying in a humid environment.