The Violet Wand Extension Cable
Your Violet Wand extension cable is an optional accessory that allows you some freedom of movement in using electrodes directly.
A proper Foam handle cable has a built-in safety gap of some kind.
This adds an additional protection against the possibility of draws on household current caused by a ground fault where your Violet Wand does not have a gap (older devices) or the presence of a safety gap is unknown (such as second-hand purchases.)
Your Foam Handled Cable / Violet Wand Extension Cable will not leak current through the foam, but a spark may jump from either end of the handle to the closest conductive surface, which can be your hand.