This lighting kit includes Ngineering's N3518 18-volt DC Power Supply, their N8102 LED Power Distribution Board, and a 12-pack of our NC7500 750-ohm 1/2-watt resistors. That is sufficient to easily power up to 28 of any of our LEDs. That's enough to take care of a big row of streetlights, a small town, lumber mill, or most any small to mid-sized scene. The resistors included are to support 3.3-3.6-volt LEDs (streetlights, building lights, etc.) when connected to the B (back-side) of the board. If lower device voltage LEDs are to be used for some connections, alternate resistor values would be required.