14V type is also suitable for 12V operation. The 12V and 24V lamps are fully ‘E ‘ approved and are therefore suitable for all exterior vehicle and other commercial applications. T-3 (10 mm) wedge. A range of T-3 1/4 (10mm) wedge base filament indicators, specifically intended for illumination in confined spaces. Suitable for use in a wide variety of applications such as push-button microswitch indicators.