Flat pack windings: The core of round-wound capacitor windings is removed and the windings are pressed flat. This method allows to make better use of the volume available in rectangular cases, however the pressing causes high tension stress at the edges of the pressed windings which impairs their electrical reliability. Moreover, the removal of the core has a negative effect on their mechanical stability. Common in traditional ALLFILM-capacitors, also still used by some manufacturers of box-shaped DC-capacitors in power electronics.