Tuxedo Vest

I don't know what's the exact size of tuxedo vest that my nephew Migs is wearing this coming weekend. His part of the singing choir in their school and wearing a tuxedo suits is a must. I'm still looking for a vest online and hoping I can get it before Saturday comes. I am panic buying right now and I don't have enough time to shop for the said vest at the mall so buying it online is the best option I have this time.