How long do the protective wings from the feat Gift of the Metallic Dragon last? The description of the Gift of the Metallic Dragon feat provided in the Fizban's Treasury of Dragons sourcebook states, in part (my emphasis):
Protective Wings. You can manifest protective wings that can shield you or others. When you or another creature you can see within 5 feet of you is hit by an attack roll, you can use your reaction to manifest spectral wings from your back for a moment. You grant a bonus to the target’s AC equal to your proficiency bonus against that attack roll, potentially causing it to miss. You can use this reaction a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.