The Alpha Communications® SS146 Class 2 plug-in transformer was designed for quick and easy installation in applications where pigtail type transformers are impractical or unsightly. It is particularly suitable for use in home or office installations, or in areas where the transformer must be exposed. The SS146 transformer comes with an extra long set screw for secure installation, once plugged in to the wall outlet. The SS146 is U.L.® Listed, and contains a built-in thermal fuse, which will blow if the transformer is overloaded or shorted. This prevents the plastic casing from igniting. Once shorted, the transformer is no longer operable. Secondary connections are made using screw terminals.