Dortronics' 3300 Series Electric Strikes from have been tested to withstand a 1,000-lb. pull test, run through 250,000 cycles, and are now UL-Listed, Burglary Resistant Electric Strikes. The series is compatible with most aluminum door frame cutouts and is suitable for most wood and hollow metal door frames. The strikes come complete 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. 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 the need for special tools.