Power-up Optimus Primal: 1) Original Product: united Optimus Primal 2) Leg Extensions: Construct-bots + Junkion blacksmith infinity warfare + TF Prime rid Hotshot parts. 3) Arm Extensions: Construct-bots + Maketoys battle tanker hand parts. 4) Flight Pack: Custom ROTF Skystalker The Power-up parts can be removed and combined together with Skystalker to form a separate battle support vehicle. Primal remains 100% still transformable, no heavy modding is required to do this. Enjoy ^_^