SDC Security Door Controls WPT Wireless Power Transfer DeviceSDC Security Door Controls WPT Wireless Power Transfer Device The WPT eliminates unsightly, exposed wires across the door gap that are susceptible to vandalism or breakage thru use and includes a timed trigger to allow for up to 90 seconds of sustained voltage, if required. The WPT transfers power wirelessly across door gaps up to 7mm (a little over 1 4), and provides more tolerance in lining up the transmitter and receiver vertically and horizontally