J Brand Luna Shift Dress in Blue. - size M (also in ) J Brand Luna Shift Dress in Blue. - size M (also in ) Cotton blend. Unlined. Side seam pockets. Exposed back zipper closure. JBRA-WD12. JB000436. J Brand proves that the denim movement toward straight and skinny is hardly a trend. With an absolutely clean, anonymous back pocket and sophisticated lines, these jeans are already a classic set for the ages.