It can be operated in a variety of ways for long-term use without harming your wrist or musclesNo limitation of operating spaceAvoid sitting close to the monitor and reduce radiation harm and eye strainPlug and play, no software requiredFit for left and right-handed usersIt is ideal for laptop users. Specifications:Compatible with Windows95/ 98/ 2000/XP/ NTunit Measurements: 3.15x2.05x1.97 inches (8x5.2x5cm)USB Cable Length: 73 inches (186cm)Color: BlackHow to use: insert your or middle finger into the hole of this mouse. Control the track ball at the angle of moving the cursor, and press the right and left buttons with your thumbWhen using the "drag and go" function, press the button in the mouse hole, which has the same function as the left button of the shared mouseUse the left button to lock the screen, then you can control the ball to roll the screen freelyMaterial: PVC Silicone Package Includes: 1 x Handmade 4D Usb Mini Trackball MouseNote: The light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3cm.