Maths were never your thing but there's one thing you're certain of. This Medium PS1+ tote bag from Proenza Schouler was made just 4U. Algebra looks pretty easy now, right? Featuring a detachable and adjustable shoulder strap, a round top handle, silver-tone hardware, a foldover top with clasp closure, internal zipped pockets, an embossed internal logo stamp and a back zip pocket.