Orion 05326 12-17mm Variable T-Thread Spacer Ring (Black)<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"> Threaded ring provides a minimum spacing of 12mm and maximum of 17mm </span></li><li><span class="a-list-item"> Variable ring provides vital spacing for astrophotography cameras and accessories like off-axis guiders </span></li><li><span class="a-list-item"> Equipped with T-threads on both ends </span></li><li><span class="a-list-item"> 1.75 inch clear diameter </span></li><li><span class="a-list-item"> Made of machined and anodized aluminum </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/51mJM15YInL.jpg" noproxy>