Relay Couplers and Timing Elays save space, installation effort.

At 6.2 mm wide, relay couplers and multifunction timing relays of Interface Relay Compact (IRC) program facilitate installation. Interchangeable relays or optocouplers allow units to be adapted to requirements,

[source: http://news.thomasnet.com/fullstory/Relay-Couplers-and-Timing-Elays-save-space-installation-effort-20031244]