The prewired 0402 warm white LEDs are perfect for illuminating the inside of your structures.
0402 LEDs are miniscule, measuring just 1mm x 0.5mm (0.04″ x 0.02″).
The wires are identified as positive (red) and negative (black). They are shipped with a resistor for powering from a 12V supply. Just ensure each LED has its own inline resistor.