T1-3/4 LENS-END E5.5 SCREWBASE 2.5V BULB PKG(15)
Itty bitty Edison style 1/4 Watt lamp with a 3/16"/5mm screw base. (type E5 or E5.5) 1/2" long overall it needs 160ma @ 2.5 V. It has a clear glass envelope that collimates the light at the end for greater intensity when viewed end on. Typically priced around a buck a each. Great for science fair projects. model railroading or anywhere tiny light is required.