Canon EF 1.4X III Telephoto Extender for Canon Super Telephoto Lenses<div style="text-align: left;"><strong>[Product Information]</strong><ul><li id="replacementPartsFitmentBullet" class="" 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"> Focal Length &amp; Maximum Aperture Magnification: 1.4x </span></li><li><span class="a-list-item"> Lens Construction of 7 elements in 3 groups </span></li><li><span class="a-list-item"> Max. Diameter x Length - 2.8" x 1.1" (72.0mm x 27.2mm) </span></li><li><span class="a-list-item"> Weight - 7.9 oz (225g) </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/41%2BX0Uab6lL.jpg" noproxy>