I'm about to start building many different type of signal; dwarf, single on a post, double or multiple on a bridge etc.. My "pet-peeves" was to find LED's that would fit and be cheap all at once. I think I have found it! I bought 2 packs ofHoliday Collection, 20 mini lights for village sets. They're small LED that can be powered by batteries (case & switch included) or by an adaptor. 20 red, yellow and green LED for $5.00! That's $0.25 each. they come already wire (string) together. They fit and look perfect for what I have in mind.