The Voodoo Lab PPEH24 Voltage Doubler is a reverse polarity (center positive) cable with a 2.5mm straight barrel end, designed to combine two Pedal Power outputs to produce either 18V or 24V. It is perfect for use with Electro-Harmonix Deluxe Memory Man, Stereo Memory Man, Electric Mistress, and other pedals requiring 24V. The Flanger Hoax also uses this cable but only needs 18V. For those needing a voltage doubler with a 2.1mm barrel connector and standard (center negative) polarity, the cable part # PPY is available.