Alvin 961X Graduated Beam Compass<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"> Two 13 inch graduated beam bars </span></li><li><span class="a-list-item"> Circles up to 48 inches diameter </span></li><li><span class="a-list-item"> Spring loaded thumb wheel </span></li><li><span class="a-list-item"> Smooth and precise adjustments </span></li><li><span class="a-list-item"> Comes complete with interchangeable ruling pen </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/310gKR3bYOL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/31%2Bc52yNv4L.jpg" noproxy>