Chromecast family Clockwise from right: Chromecast Ultra ($69), Chromecast ($35), and Chromecast Audio ($35). Available from Google.

A Chromecast is one of the easiest and least expensive ways to stream video to an otherwise not-so-smart TV, or a dumb speaker. For less than $70 and with just a couple of connections you can stream video and (or) audio from just about any phone or tablet or computer. And there are two species of Chromecast — one for audio only, and one for video.

The question, then, is which one is right for you. Let's explore.

Our top pick: Chromecast Ultra ($69)

See at Google

This is the big daddy. Sure, it's a small puck-shaped dongle just like all the other Chromecasts. But this one is the most future-proof of the two video options. It lets you stream video from a phone or tablet — Android or iOS — or from a Chrome browser. And it'll do it up to 2160p resolution. That's 4K video.

You might not have a 4K display yet. But if you're thinking of getting one sometime in the near future, I'd go ahead and pick up the Chromecast Ultra. Better to spend $69 now than picking up a lesser option and deciding you want this, too, later.

Chromecast ($35)

See at Google

This is the second generation of the original Chromecast. It's what you'll want to get if you're extending a 1080p display — as that's this highest resolution this dongle will handle. I wouldn't think of it as a lesser Chromecast, per se — just one that you'll want to use with a television that maxes out at 1080p.

And given the price, there's no reason why any TV that doesn't already have Chromecast support baked in shouldn't have one of these sticking out of an HDMI port.

Chromecast Audio ($35)

See at Google

As the name implies, this Chromecast is meant for dumb speakers or stereos that don't otherwise have smart connections. You run a 3.5mm audio cable from the Chromecast Audio into an aux port, and away you go — "casting" audio from podcatchers or music apps into a system that was previously confined to local playback.

Again — this one doesn't do video. It's meant for a stereo system. So it's more niche. But still darned useful.