A cellular telephone casing, for enclosing and protecting a cellular telephone without interfering with the normal functionality of the cellular telephone, the casing having walls made of vinyl covered foam which define an interior volume for fully enclosing the cellular telephone in a substantially waterproof protective covering. The two ends of the belt are respectively connected to the first housing and the third housing, which can be buckled together quickly. In the table magnifier, the focus length of the lens unit is adjustable by controlling the length of the arm unit.