Pins on either side of the base lock these bulbs into sockets. Pins are directly across from each other.

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.

Commonly used in signs, instruments, indicators, and flashlights.

Use these as replacement bulbs in stack lights.