CST2545W (L-TRAC) USB Wired High Performance Trackball， Black - Made in the USA<div style="text-align: left;"><strong>[Product Information]</strong><ul><li id="replacementPartsFitmentBullet" class="aok-hidden" data-doesntfitmessage="We're not sure this item fits your " data-fitsmessage="This fits your "><span class="a-list-item"><span id="replacementPartsFitmentBulletInner"><a href="#" class="a-link-normal hsx-rpp-fitment-focus">Enter your model number</a>to make sure this fits.</span></span></li><li><span class="a-list-item"> Laser Precision Tracking </span></li><li><span class="a-list-item"> Rugged Construction made of High Impact ABS Plastic </span></li><li><span class="a-list-item"> Width 3.75" (9.5cm)， Length 6.75" (17.1cm)， Height 1.75" (5cm) </span></li><li><span class="a-list-item"> Ball Size: 2.25" </span></li><li><span class="a-list-item"> Resolution: User selectable 400， 800， or 1600 counts per inch </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/31slC3JMYML.jpg" noproxy>