With Apple equipping all its recent Macs with Thunderbolt 3 ports, using an external GPU – or eGPU – is a very convenient way to boost graphics performance. Apple already sells two of them, and it has just added a third: the Radeon RX 560 …

Apple currently sells two Blackmagic eGPUs, the eGPU and eGPU Pro (review), priced at $699 and $1,199 respectively.

But a significantly cheaper option, Sonnet’s eGFX Radeon RX 560 Breakaway Puck, has just been added to the online store, with both delivery and store pickup available for Monday. This suggests it will go on sale in physical stores the same day.

Priced at $399.95, Apple says it is ideal for the 13-inch MacBook Air or MacBook Pro, 21.5- inch iMac or new Mac mini.

Apple first announced official support for the RX 560 back in February.

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.

Inside the box is the RX 560 itself, with 4GB of GDDR5 memory, and it comes with a power supply and short (0.5M) Thunderbolt 3 cable capable of supporting the full 40Gbps bandwidth.

The unit offers 60W power delivery to keep your Mac charged, enabling single-cable use.

The RX 560 isn’t one of the most powerful eGPUs out there, but will still provide worthwhile improvements to the graphics capabilities of Apple’s lower-end Macs.

We previously checked out the company’s Breakaway Box 650W (available elsewhere for the same price), as well as the PowerColor Mini Pro and more powerful (and more expensive) RX 580 Gaming Box.

Check out all our eGPU coverage and reviews here.