Dual Led Blinker Unit perfect for Model railroaders. This unit measures 1" x 1" x .5" and runs off 9-12vdc power. You pick color. LED's flash 1-2-1-2 etc. Great for any hobby! Flashes Back and Forth Green & Yellow. This is NOT the R2 D2 Flasher. These are made in USA not overseas crap circutry.