Venturi Injectors (Injectors) work by forcing water through a conical body which initiates a pressure differential between the inlet and outlet ports.  This creates a vacuum inside the injector body, which initiates ozone suction through the suction port.
Characteristics:
 very high ozone mass transfer rate (up to 90%)
 
 requires water pump to initiate suction
 
 efficiency rarely decreases over time
 
 no moving parts