The Dortronics 3300 Series are now UL-Listed Burglary Resistant Electric Strikes. They were tested to withstand a 1,000-pound pull test and run through 250,000 cycles. Made by Dortronics of Sag Harbor, New York, the series is compatible with most aluminum door frame cutouts and is suitable for most wood and hollow metal door frames. The strikes come with an ANSI strike plate for hollow metal door frames or with a 9-inch-tall strike plate for installation on wood door frames. Both styles can accommodate a deep door latch keeper. Built with a stainless steel jaw and strike plate, the strikes convert from fail-secure (the door is locked in case of a power failure) to fail-safe operation (the door is open in case of a power failure) without special tools. Input power is field-selectable to meet most voltage requirements. An optional latch bolt monitoring switch provides status and facilitates use in access control systems.