Says "Sold by Amazon" and I've heard horror stories about 3rd party sellers, so I tried to cover my 6 in that regard.
That's good. If it only had specified "shipped by" Amazon, that could have been one provided by a third party vendor. Bearcat Warehouse (using the name "Police Scanner Outlet") and Zip Scanners also sell on Amazon, with amazon providing the shipping.
Rob, I checked with Autozone and O'Reilly's and they don't have any filters for this unit.
Ok, it's driving me nuts!
The filter being referred to is not a physical filter that you install. Look at the Wiki page link RobDLG provided
above. That explains filters and their settings for the SDS100 & SDS200.
The filter is a setting made in your Favorites list, For a trunked system, it's under the Site Options tab in Sentinel and on the scanner.
In your Profile in Sentinel, you can set a filter to be used on all your systems, That's why the screenshot shows as "Global", because for that site, I'm using a default filter setting. However, instead of choosing Global, I can set a different filter for one or more specific sites.
The "Global" setting, if used, is set in the Profile.
I'd still suggest, as Whiskey3 posted
above, that you post your file & let one of us take a look, just in case something got overlooked. That can happen to any of us (at least the ones that aren't too shy to admit it), and sometimes a second, or third, set of eyes spot something that is out of place.
It's certainly not impossible that you got a defective unit. There haven't been a lot of "bad units" out of the box, but that's not impossible with anything electronic or mechanical.