Optical Crystal Mouse Model No.: SJ-MS-261 Visit our website to get more details. Description: 1) Optical mouse with new design 2) Ideal for home or officer user, 800 CPI 3) No ball, no dirt, no cleaning. 4) Optical scanning technology. 5) 2 programmable buttons and 1 scroll. 6) Scroll button: vertical or horizontal scroll by simply clicking on it. 7) Convenient for left and right hand user 8) PS/2 , USB and U/P combo ports available 9) Product dimension:98*56*29.5mm, N.W.: 81.5g(PS/2) Specifications: 1) Compatible with Windows 2) Drivers for Windows 95 / 98 / 2000 / Me / XP and instructions are included USB Plug