Permanent shorting bars is another offering. Tin-plated copper/brass bus links, which rest below the top surface of the terminal blocks are used with sleeves and mounting screws to achieve a permanent cross connection. Bars are available in 2-3-4-10 position lengths, and may be cut to size.  For switchable connections, two position removable shorting links are available. Sleeves and screws are ordered separately. Test sockets are used for checking out circuits. The test socket screws into a tapped hole in the terminal block current bar, and accepts a standard test plug. Sockets can be left permanently in place, or only used as required. Shorting links for spring clamp blocks are insulated, two-position push-in links that are utilized to bus adjacent spring clamp blocks on a track assembly. Alternate links perform the same function, but the contact spacing is designed for alternate (non-consecutive) blocks. Wired shorting links will connect any two blocks spaced up to ten positions apart. Shorting links for stud-mount blocks are insulated and uninsulated links, offered in both permanent (ring tongue) and removable (fork tongue) styles. They are available in 2, 3 and 4 positions.