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

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

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

These bulbs are sized to fit tight spaces such as indicators and vehicle lights.

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.