The Dwarvin HO Scale Turnout Signals for 2 Wire Snap Bipolar Switch Machines Kit for system is designed to integrate with snap twin coil two-wire bipolar solenoid-style switch machines Kato, Rokuhan, Rapido Trains and any others using two-wire snap machines. Kits are available with or without three dwarf signals. The system is available with or without signals and power supply. A unique feature designed into this system is that it remembers the direction of the turnout from the last time it was used, even when power has been interrupted. The system can be used with either AC or DC power, directly from the turnout power. You can also cascade each controller so that you only need to power one and all are powered. This has a unique advantage when using the product in a yard ladder. Only one power supply needs to be used as all the other controllers can get their power from that first one, thereby reducing complexity. The Turnout Signals for 2 Wire Snap Bipolar Switch Machines kit is one of many fiber optic lighting and signaling products from Dwarvin.