GepRc DarkStar20 Tattu 2S 550mAh Battery bay mount

Printed with default supports on X1C in PETG.

It's not a hard model to make, but it takes a few iterations to get the tolerances right.

You will have to cut the existing mounts, but you'd need to anyway if you want to mount anything other than the battery it's made for (this mystical battery is not publicly available)