Cartridge Pleat curtains have hand-sewn and stuffed pleats and as a result can take up more room when drawn so either order a longer pole or be prepared to lose some light.  Due to the uniformity of the cartridge pleats they can look stunning when worked into a geometric pattern and look extremely elegant when made up in a plain fabric.  As with all curtains that have hand-sewn pleats I would recommend that they hang below the pole to allow the pleats the space to fall as they should.  Cartridge curtains look elegant either skimming or tumbling onto the floor.  Cartridge Pleat curtains can be interlined and have either cotton, thermal or blackout lining.