From GameWatcher: “Synthesis Scanner is a special targeting tool in Warframe that allows users to see enemies through walls, measure distances from one point to another, and synthesize various types of DNA for various purposes.
The Synthesis Scanner can be purchased off Cephalon Simaris in batches of 25, but through its variety of upgrades, you can also unlock infinite charges for the scanner if you’re clever with your investments. We’ll go into more details below.”
Source: N4G PC Warframe Synthesis Scanner – How does it work?