The Directrac system separates the stand from the message, and this double-sided cartridge is the message half: a poster on each face for 360-degree visibility in a traffic aisle, held in an insert that lifts out of the stand as a unit. Keeping extra cartridges pre-loaded turns a poster change into a swap rather than a mid-floor dismantling. It comes in the two Directrac sizes — 22-by-28, and 24-by-36 for use with 40-inch or taller posts — each size-matched to its stand, in a wrinkle black finish. It is a dependent accessory made for the Directrac Sign Stands. SKU 50-4580MB.