External GPU (eGPU) support for your Mac became a reality thanks to macOS Mojave. In fact, Apple Stores have been offering BlackMagic’s $699 Radeon Pro 580 and $1,199 Vega 56 eGPUs for months now. But if you’re looking for a cheaper eGPU option, the iPhone maker is now selling Sonnet’s affordable $400 Breakaway Puck featuring Radeon RX 560 graphics.

Apple notes that the Sonnet eGFX Breakaway Puck Radeon RX 560 External GPU, as it’s named, is meant to speed up graphics-intensive games on both internal and external displays.

It features AMD’s Radeon RX 560 graphics chip with four gigabytes of GDDR5 memory and supports up to four 4K displays. It’s perfect for the new MacBook Air and MacBook Pro notebooks. It’ll also support any Thunderbolt 3 Mac.

Delivery starts Monday, when the product will go on sale in physical stores.

From the Apple Store description:

With an AMD Radeon RX 560 graphics card inside, Sonnet’s eGFX Breakaway Puck Radeon RX 560 is an extremely-portable, high-performance, all-in-one external GPU that accelerates popular graphics-intensive games on 13-inch MacBook Air or MacBook Pro, 21.5- inch iMac, or Mac mini with Thunderbolt 3 ports.

For GPU acceleration when you’re on the road, the Puck conveniently packs with your MacBook in a backpack or computer bag. Thanks to the included Thunderbolt 3 (40Gbps) cable that provides 60W of Power Delivery, you can connect the Puck to your 13-inch MacBook Air or MacBook Pro for power and charging—even when not in use—so you can leave your power adapter behind.

The Puck isn’t all about play—it’s also a multi-display graphics dock. When you need to expand your view, the Puck supports up to four 4K displays via three DisplayPort ports and one HDMI ports, all connected to your Mac with a single cable.

eGPU is a great option in this day and age of sealed computers, letting your Mac notebook access additional graphics performance by connecting to an external graphics processor.

Ports (left to right): 3x DisplayPort, 1X HDMI, 1x Thunderbolt 3 and power

An eGPU will accelerate all apps that rely on Metal, OpenGL or OpenCL, including professional video editing apps, 3D games, VR content creation software and more.

eGPUs come in their own external enclosure with cooling, power supply and a bunch of ports allowing you to connect your computer to additional external monitors and displays.

Sonnet’s box is best suited for the new MacBook Air, Mac mini and 21.5″ iMac

You can charge your Mac notebook while using an eGPU, use it in clamshell mode, connect an eGPU on the fly and even connect multiple eGPUs. To use an eGPU, your Mac must have Thunderbolt 3 I/O and run macOS High Sierra 10.13.4 or later. While Mojave’s eGPU support isn’t yet fully fleshed out, it’s completed enough to be used on an everyday basis.

Check out the list of supported eGPUs in Mojave in a support document on Apple’s website.

The new Sonnet Radeon RX 560 is available through the online Apple Store and Amazon for $400 a pop. A more powerful version featuring AMD’s Radeon 570 GPU can be had via Amazon for an additional $100.