This is not an arcanowave schtick per se, insitead it is an indication that Arcanowave users have access to Blast schticks. These are a different kind och schtick and bought separately from normal Arcanowave schticks, but they use the Powers skill and the general rules on arcanoware.
Most arcanoblasters have only a single blast and generally few metablasts. Almost all have Focus, but it is not mandatory. If you don't have it, you have a symbiote. The Symbiote Blaster actually lives mostly inside your body, being visible only as a small protrusion of ARB on a hand or in the face. It is thus almost impossible to spot.