Abstract: A combined mouse and trackball having its control ball (15) extend past cover 1. Cover 1 has neck hinges (5) so that it pivots in relations to opposing cover (17). A cable (33) at the front communicates with the computer receiving the control signals from the ball. A switch (43) reverses the significance of front-to-back signals from the ball depending on whether an actuator (45) integral with cover 1 engages the switch. In the closed position of cover 1 the bottom of the devise is flat and the ball is upward for use as a trackball. In the open position of cover 1 the device is formed into a mouse with front and rear surfaces (67, 69) to support the ball for frictional movement on a table (71). Latch surfaces ((25, 57 and 25, 65) hold the covers in the two positions until they are manually released.