Wireless Keyboard Space Saver with Optical Trackball By Ergoguys Built-in Track Ball & Mouse key, Scroll Wheel; Keyboard & Mouse in one. 2.4 GHz wireless with 8 channels. 360-degree navigation. USB Receiver Connector. Bidirectional RF frequency. Notebook keyboard module makes this perfect for handheld operation Two choices for mouse browsing: 800 dpi Optical Trackball & Scroll Wheel with mouse button