Hi Marcelo, is there any definiton for detachable parts as well? I'm wondering if that "additional" term wouldn't mean something different. Example: in a dental driller composed by a driver unit, a "detachable" motor hand-piece and a footswitch (also detachable), is the hand piece an accessory? Even if they're sold together, shipped in the same box/package? Why would that be so important to have a SN and a date in the hand-piece?