A 1976 Spurrell LED elevator floor indicator sign, Paid $18 for this in a flea market. This sign has a total of 148 LEDs and goes from 1 to 10. I have bought and turned this item into a decoration piece. Outer casing is scrap wood. Operation of the LEDs is achieved by a 555 Timer IC and a 4017 CMOS counter. 10 power transistors salvaged from old computer monitors handle the switching of each set of LEDs on each number. Two controls on the back of the case control the flash speed of the LEDs. All LEDs on this work very well.