4.5 volt Xenon mini lamp replacement flashlight bulb commonly used in many flashlight models. E-lectronics.net has 3 versions of this lamp (4.5v, 6v, and 7.2v) to accommodate different voltage batteries from the Lithium CR123 at 3  volts to the Li-ion RCR123 at 4.2 volts.

Dimension: 6.15 mm diameter x 17.8 mm Long

Please reference the following chart to help you select the lamp model that is right for you. These measurements were acquired by e-lectronics, lumen output was measured as total flashlight output including any reflector and lens loss, not total lamp output.
 

Lamp Model	Battery	Number of Cells	Peak Voltage	Nominal Voltage	Amperage at Load	Lumens	Run Time
4.5v	CR123	2	6	5.6	.78	50	100 min
4.5v	RCR123_3.0ic	2	6.8	6	.85	75	45
6v	CR123	2	6	5.6	.82	55	90
6v	RCR123_3.0ic	2	6.8	6	.93	80	30
6v	RCR123_3.7	2	8.4	7.2	1	125	30
7.2v	RCR123_3.0ic	2	6.8	6	.7	40	50
7.2v	RCR123_3.7	2	8.4	7.2	.85	90	45