If you’ve wanted to give an older Mac the ability to output to HDMI—useful for connecting some MacBooks and prior-generation Mac minis to most HDTVs or monitors—there are plenty of inexpensive options. But there’s also an affordable adapter that’s solidly built and more future-proof than most. Sold for only $15 through Amazon.com, Belkin’s Mini DisplayPort to HDMI Adapter 4K/Ultra HD Compatible ($35) adds an HDMI port to any Mac with a Mini DisplayPort or Thunderbolt port. And if your machine has the right hardware, GPU, and version of OS X, you may be able to connect an Ultra HD 4K display to it, as well.
Assuming that your Mac has enough graphics horsepower to actually drive a 4K display, it probably also has an HDMI port capable of making that connection, but if not, Belkin’s adapter can work. The jet black cable is five inches long, transforming a Mini DisplayPort 1.2 or Thunderbolt 2 port into an 18GB HDMI 2.0 port with support for 32 audio channels and up to 60FPS 4K video; machines with older Mini DisplayPort or Thunderbolt ports are capped at pre-4K resolutions. You have to supply the HDMI cable yourself, though Belkin sells a larger version with a six-foot HDMI cable for $10 more.