A device having a first side and a second side, comprising a lower housing, an upper housing tacked on the lower housing comprising a first edge located at the first side and a second edge located at the second side, a bracket and a biasing assembly. The bracket is configured to tilt the first edge of the upper housing away from the lower housing. The biasing assembly is configured to rotate the bracket to tilt the first edge of the upper housing away from the lower housing. The biasing assembly comprises a slider board and a resilient member, one end of the slider board is pivotably connected to the upper housing adjacent to the second side of the device, the resilient member has a first end connected to the first housing, and a second end connected to the other end of the slider board.