No. The FlowBlaster Accessory requires the use of the Duct Blaster fan to match the flow either coming out of a supply register or going into an exhaust fan or return grill. You do not need to buy an additional Duct Blaster fan. The FlowBlaster Accessory comes with all the parts needed to configure your Duct Blaster fan.
Please note that TEC discontinued sales of the FlowBlaster in January 2017.