A silver-colored steel backboard support or back connector fitting . It is a small hardware piece often used for stabilizing furniture backing. Replacement parts can be found on sites like IKParts .
The part number most commonly refers to several distinct items depending on the manufacturer or brand. Here are the most likely "pieces" you are looking for: Common Hardware & Parts 122739
A parallel stop (also called a longitudinal attachment) for table saws, specifically compatible with the Makita 2704/2704X models. Other Specialized Items A silver-colored steel backboard support or back connector
An 18-tooth spur gear (12 DP / 14.5 PA) compatible with Lippert (LCI) through-frame slide-out systems. This is a heavy-duty metal gear used to repair jamming or worn components in motorhome sliding cabins. 122739