PS/2 3-Button Optical Mouse with Scroll Wheel, Model M850 by BTCPS 2 3 Button 3D Optical Scroll Mouse Agilent enabled 1,500 optical scans each second **NOT USB, MUST BE CONNECTED TO A PC THAT HAS A PS 2 PORT** 3 Button 3D Optical Scroll Mouse. 1,500 optical scans each second. Detects most kinds of surfaces including wood, plastic, cloth, etc. Product Dimensions (L x W x H): 213 x 221 x 56 MM Product Weight: 1. 1 LB