Can be the UV light source.

Type	spectrum  response	igniting  voltage(Max)	operating  voltage	operating current	sensitivity (Min)	Diameter	height
Z-09	190-290nm	160VAC	220±15%AC	0.5-5.5mA	10ms(Max)	7mm	22±2mm
Z-09A	190-290nm	160VAC	220±15%AC	0.5-5.5mA	10ms(Max)	9mm	37±2mm