If some one has to buy DAZ Olympian Outfits to use your Mat Pose, it is an add on. Morph targets are add ons (because you need to own Vicky to use the morph target for heir head, i.e.) A Morph for Posette is a stand alone, because Posette is anyhow included in Poser. Stand alone items are objects or figures you can use without to buy or to load or to download something else before you use it. :-)Guitta