Fischer Elektronik Hollow-fin Cooling Assemblies with Axial Fans. Fischer Elektronik hollow-fin cooling aggregates with fitted axial fans offer a versatile and efficient cooling solution in high powered applications where heat dissipation is only possible by forced convection. With a range of sizes to suit an array of requirements, Fischer Elektronik cooling aggregates are ideal. Geometry of hollow-fin optimising the airflow Particularly effective heat dissipation Compact construction Milled flat semiconductor mounting surface