Oyafune Suama's Elmo shirts
Elmo (エルモ Erumo?, Yen Press: Ermo) is a clothing brand existing outside of Academy City that markets toward teens. They are apparently famous enough for the likes of Accelerator to notice that they are for teens.
Misaka Misuzu wear clothes from the brand, among others, such as Az, Scale, and Russiv.[1][2]
Oyafune Suama wear shirts from the brand.[3]