A device includes a housing defining a first opening, and a casing fixed within the housing defining a second opening opposite to the first opening. The device also includes a sliding member slidably received in the casing, and a stand pivotally connected to the sliding member including an end received in the first opening. A retaining member is slidably connected to the casing to magnetically attract the sliding member to retain the sliding member at a predetermined position. An ejection mechanism is arranged within the casing to be pushed by the retaining member to push the sliding member to move the end out of the first opening.