While there are plenty of SD cards that are designed to perfectly sit in the MacBook's SD card slot and be used for extra storage, none of them integrate with the computer quite like this one.
A new SD card called the TarDisk Pear does, in fact, sit perfectly in the SD card slot, but beyond that it is also able to actually merge with the MacBook's solid-state drive to offer users one single hybrid drive and allow for better file management.
The SD card is built using a brushed aluminum, meaning that it will blend in with the rest of the MacBook design, and it includes a built-in installer that basically helps users turn their standard SSD into a fusion drive. What this means is that users don't have to manage two drives on their computers and decide which files go where. Instead, the computer is just tricked into thinking it all of a sudden has way more storage at its disposal.
Of course, performance could certainly be an issue, so the software on the SD card makes sure that the actual MacBook drive is always the preferred place to store files if there is still space left on the drive. Once the MacBook drive is full, the TarDisk Pear will try and keep the most-used files on the MacBook hard drive so that they are more readily available to the operating system.
There are a few things to remember with an SD card like this. Because of the fact that the SD card, on a software level, merges with the MacBook drive, there could be important system files on the SD card, meaning that you probably shouldn't remove it at any point. Instead, you should probably consider the SD card slot out of commission.
The TarDisk Pear is also not cheap, coming in at a cool $149 for the 128-GB version and $400 for the 256-GB version. Keep in mind that the upgrade from 256 GB to 512 GB on the Apple website for those buying a new MacBook is $300, so if you want more memory on a new computer you should probably just buy the upgrade rather than buy a new computer and an SD card.