that link appears to show the Phihong 5v 3a wall-wart
I suggested, however I've no idea why Mouser list it having a 'suffix' of R
, whereas on the manufacturer's datasheet pdf you'll see it's 'suffix' is shown printed by Phihong as P
You could of course give Mouser a call to ensure it comes with a USA power-plug that fits your wall socket.
BTW - there are, by my standards, about 8 of us 'regulars' who all try hard to resolve user problems
as Roku themselves no longer participate in offering such solutions