Size: 8.7 x 5.3cm; Packaging: cardboard; Commercial power: button battery model CR1216 (included, replaceable); Its size is similar to a credit card, you can easily in the wallet; Actually such a small card can be used for lighting, its shape is very interesting, there is a light bulb shape hollow, the time when the need for lighting can be the "light bulb" stand up, you can light up; Can be used as a gift.