A one-time-use glass bulb enclosing a pyrotechnic wire filament that burns out, generating a bright flash, when an electrical current is run through it.

Light source based on ignition of combustible metal wire in a gas filled transparent envelope. Popular sizes are usually blue-coated to give light approximating to daylight.

replaceable bulb for use in expendable flash units. A glass bulb contains a pyrotechnic wire or paste which burns out in a brilliant flash when a low voltage firing current is applied.