Per the Magpul webiste "The Magpul SSG Selector Set are drop-in, dual sided selectors for the FN SCAR family of weapons. Designed at the request of a deploying military unit who wanted more positive control of the selector, the SSG are compatible with military-issue select fire MK16 & MK17 weapons, as well as the civilian semi-automatic SCAR 16S & 17S rifles. The SSG are direct replacements for the OEM selectors, and require no permanent modification to the weapon system. Simple install utilizing existing set screw (not supplied)." I bought these from Aimsurplus.com for $18.95 plus shipping. They are not metal, they are some sort of plastic, but very durable.
The selectors were purchased because I wanted an upgrade to the OEM selectors, which do the job, but suck in terms of ergonomics, overall size and flow of the SCAR when compared to the Magpul selectors. I threw my OEM selectors out since I will never need them again. For less than $20 you get the "should have been" standard. You can google an image of one if you want, but this one is better. The SCAR comes from the factory with an ambidextrous short-throw 45 degree selector. OEM selector comes off with a very small screw driver, Magpul selector goes on (I believe it comes with some blue Loctite) then you screw it back using the screw provided. Takes less than 5 minutes and you get an awesome looking setup.
Nice thing about this selector is that Noveske and Magpul decided to make a short throw selector setup together for the AR15. Link from Midway, just in case you are interested. So if you run one of these on your SCAR you can get the same selector for your AR15's and have some cross-platform functionality familiarity.
