These bulbs are small, but very bright, so they're often used in flashlights and optical instruments such as projectors and microscopes.

These bulbs are sized to fit tight spaces such as signs, control panels, indicators, and flashlights.

Bulbs have two filaments, which operate at different brightness levels.

Bulbs have two filaments, which operate at different brightness levels.

These miniature bulbs are sized to fit older telephone switchboards, signs, instruments, and indicators.

Offset pins on the base lock these bulbs into sockets. One pin is slightly higher on the base than the other pin.