If you want to get the upcoming iPhone 8, you’ll probably need to buy it the second it goes on sale.

According to KGI Securities analyst Ming-Chi Kuo, who has been following the iPhone 8 in the supply chain all year, the phone will be unveiled and will launch at the same time as Apple‘s other two expected iPhones, including the iPhone 7s and iPhone 7s Plus.

Kuo said the phone will launch in black, silver and gold, suggesting that rose gold isn’t going to be an option.

Kuo warns that the device, which Kuo once said was delayed, will be in extremely tight supply with only about 2-4 million units available, according to AppleInsider, which saw the note.

It’s rather common for Apple’s new iPhones to sell out of stock rapidly after they go on sale, sometimes taking weeks or months for additional supply to become available. That was the case earlier in 2017 when Apple launched the iPhone 7 Plus, for example, which ended up being more popular than Apple expected.

The iPhone 8 may be hard to get at first, but Kuo says Apple will ramp up production in order to build 45 – 50 million iPhone 8 units this year, according to AppleInsider.