The Mtubecap is made of polyprophylene. It combines a high degree of dielectric strength and low residual inductivity with a very compact form of construction. It has been developed as a high-quality technical alternative to high-voltage electrolytic capacitors. The advantages over electrolytic capacitors are: Lower ESR, Longer Service Life, and Self-healing properties. The TubeCap contributes to a finer, livelier and higher definition sound impression.