SD cards are slow and unreliable as computer storage, but Transcend’s new JetDrive is a great way to add extra storage to your new M1 MacBook Pro without paying Apple’s absurd prices.

Transcend’s new JetDrive adds storage to the new M1 MacBook Pros by simply sliding it into the SD card slot. It costs $250 for 1TB, compared to $400 to upgrade from 1TB to 2TB at the time of purchase. The two options are far from equal. Both have pros and cons. And if you’re already running out of space, the JetDrive has one big advantage: You don’t have to buy a whole new computer just to add more storage. But it’s also slow.

“[I’m] a MacBook Pro user who purchased a 1TB SanDisk Extreme Pro portable SSD for this very reason,” content creator David Woutersen told Lifewire via email. “SD cards like Transcend’s new JetDrive cards may seem like a good idea at first, but if you’re anything more than a casual Mac user, the storage will feel sluggish and slow down your workflow.”

Transcend’s JetDrive has been popular for years, and the new model is more of the same, just with more storage and designed to fit snugly into the SD slot on the new 14- and 16-inch MacBook Pros, with only a slight protrusion so you can pry it out with your fingernail. But it’s still a regular SD card.