This black Saint Laurent Envelope leather cross body bag features a combination of matelassé, vertical and diamond quilting. Made in Italy, it has gold tone hardware, a sliding chain and leather strap, back slip pocket, fold over flap top, YSL plaque and hidden closure. In mathematics, an envelope 'is a construction that generalizes the operations of "exterior completion".' We don't know what that means, but this Saint Laurent Envelope bag certainly completes our exterior (AKA outfit).