extension ring

extension ring

or

extension tube

n
(Photography) photog a spacer element that can be fixed between the camera body and the lens to increase the distance between film and lens and allow closer focus than would be possible without it
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
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Extension Ring is milled from one piece of aluminum alloy.
Or look for a new toilet with a bigger base that will cover the tile, and use a flange extension ring. If you can't find either one, you can try this patch.
The low-profile units with universal mounting and two-wire installation are easy to install on a standard electrical box without an extension ring. A speaker mounting plate and snap-on grille cover streamline installation and eliminate the need for mounting screws.
Mobile operator Vodafone UK has introduced its Mobile Exchange service for companies wishing to provide their employees with a method of having their personal extension ring through to their mobile phone.
If it's recessed more than 1/4 in., use a plastic extension ring. You'll find both in the electrical department at home centers.
Next, raise the toilet flange by adding an extension ring or two (Photo 13).
We recommend that you use two to three wraps of electrical tape to cover the terminal screws of receptacles and switches when you're installing them inside a metal extension ring (shown) or onto a metal plaster ring.