For simplicity's sake we'll refer to the technology as 4K here, but you will find it called Ultra HD just as often - it ... rate (HFR), which guarantees 60fps - something you might not necessarily ...

There is also an updated Streaming Stick with that four times Wi-Fi range, voice remote and HD quality playback for $50 (£38). The Roku Ultra is the top-end device which offers 4K, HDR ...