It can be operated in various ways to ensure long-term use without strain on the wrist or muscles No limitation of operational space Helps reduce eye fatigue and promotes comfortable viewing distance from the monitor Plug and play, no software required Designed for both left and right-handed users Ideal for laptop users Specifications: Compatible with Windows 95/98/2000/ME/XP/NT Unit dimensions: 3.15 x 2.05 x 1.97 inches (8 x 5.2 x 5 cm) USB cord length: 73 inches (186 cm) Color: Black How to use: Place your index or middle finger into the hole of the mouse Control the trackball to move the cursor and press the right and left buttons with your thumb For drag function, press the button inside the finger hole which performs the same action as the left mouse button Use the left button to enable screen scrolling functionality Material: PVC silicone Package includes: 1 x Handheld 4D USB Mini Trackball Mouse Note: Lighting and display settings may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3 cm