This device allows you to interface Logic Rail signal boards to each other when signals cross booster power district boundaries. The LR-OPTO4 is a kit that requires assembly. Because it can be used in a variety of ways, it does NOT include cables or wire -any wire from 22 to 28 AWG will do. This kit can be used to interface various other devices together as long as it doesn-t exceed the 3 mA limit of each opto output. We do not recommend trying to save money using it, rather than the OPTO4BDL, to interface Logic Rail to BDL162s or BDL168s. By the time you add the cable and resistors, you don't save much money and you don't get the instructions necessary for that connection.