Nearly Silent Helicopter

At only about 20 seconds away this helicopter was pretty much silent. It's of course loud when it's close, but I was amazed at how short of a distance it was before you'd never know it was there unless you were looking at it. Someone help me out in the comments with the type of helicopter this is. I'm sure it's not anything special, but I don't know anything about the different models of aircraft and it made me wonder how quiet one could be that was specifically designed for stealth. My understanding is that this was kind of a meet in greet between the Tennessee National Guard and local fire departments 2 of 3 years ago when the National Guard was going to start working with local rescue operations in remote areas, when needed.