20x 0.425 Watt 2.5 Volt Incandescent Bulbs Style A Base, Check Pictures For A Measurement Diagram Indoor/Outdoor Bulbs One Or More Can Burn Out And The Others Stay Lit Standard Glass Mini Bulbs Only Use In Strings That Use This Wattage And Voltage Bulb, Common On Most 50, 100, 150 and 200 light strings. 20x 2.5 Volt .425 Watt red glass with green base mini incandescent bulbs. 20 New replacement bulbs. This is the style where one or more can burn out but the others stay lit. Indoor/outdoor bulbs. You can also remove these bulbs from their base to use a different style or color of base to use in any strand of lights that uses a standard 2.5 Volt .425 watt Incandescent mini bulb. Style A base measures .44" long, with a inserted depth of .36" and an inserted diameter of .25". Please see the pictures for a measurement diagram, there are many different base styles. Will only work in strings that use this wattage and voltage of bulbs, using in the wrong string can cause the bulb to be dim or burn out quickly.