The CT-3BG circuit board is the same as in the CT-2B control unit. The difference is that the CT-3BG (the "G" represents "Gate") is conformal coated with acrylic for direct installation in an automatic gate operator. The board is less than 4 inches square. The CT-3BG is connected to the free exit terminals on the gate operator. The adjustments, multi-component aspect, and variety of sensor probe cable lengths differentiate it from the GateMate free exit system. The adjustments, multi-component aspect, and variety of sensor probe cable lengths differentiate it from the GateMate free exit system.