What is part number B661-52821 for MacBook Air M4 13-inch?

Hi,

My MBA M4 13” is having a repair done at an “Apple Premium Partner” called Select. They have informed me that the problem was with the top case (B661-50062) but now they have changed the part ordered to B661-52821. Could anyone let me know what that new part is? I’ve found nothing about it online.

Posted on Oct 21, 2026 8:00 AM

2 replies

Owl-53

Level 10 (123,805 points)

Oct 21, 2026 8:10 AM in response to ashar281

I have confirmed that B661-50062 is the top case assembly for the 13-inch MacBook Air M4 (2025).

However, I have not been able to find any reliable information online identifying the new part number, B661-52821.

The top case is the main upper chassis, including the keyboard and palm-rest area.

Depending on the specific assembly, it may also include the battery.

There are a few possible reasons Apple may have changed the part number:

Part supersession: Apple may have replaced the original part number with a newer one.
Different configuration: The new part may have a different keyboard layout, colour or assembly specification.
Parts availability: Apple's service system may now specify an alternative part.

Unfortunately, I have not been able to confirm which of these applies in this case.

I would suggest asking >> Select << to confirm whether B661-52821 is the official replacement for B661-50062 and, if so, whether it includes the battery and retains the same keyboard layout and colour.

HWTech

Level 9 (78,350 points)

Oct 21, 2026 12:53 PM in response to ashar281

Apple sometimes updates the parts giving them another new part number. Usually the newer number is the more recent part. No idea why. Apple is very mysterious.