The default outfit of Nijisanji EN's Sonny Brisko, as seen on Twitter and post #5159639.
His default outfit is composed of a grey shirt dress shirt, bulletproof vest/yellow shirt, black jacket, black pants, black combat boots, mismatched gloves (black one on the left and a fingerless yellow one on the right), arm belt on his left arm and a thigh belt on his right leg, and one bag for each belt.
This tag implicates sonny_brisko (learn more).