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

Pins on either side of the base lock these bulbs into sockets.

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

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

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

Fit these bulbs in tight spaces such as signs, control panels, indicators, and flashlights.

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