Box Frame Linear Solenoids Ledex / Johnson Electric Box Frame Linear Solenoids are available in AC and DC versions and provide slightly higher force output and higher resistance to environmental conditions. This technology offers life up to 5 million cycles and a variety of size, force, and stroke options. Ledex / Johnson Electric Box Frame Linear Solenoids offer an economical design for high-volume applications, continuous or intermittent duty, and on/off operation that is common in applications such as vending machines and automated door locks.