Extruded anodes have high current to weight ratio, are suitable to be used in where a small diameter anode is required to give enough cathodic current. 
CorrTech supply extruded anodes in both high potential (Mg-Mn alloy) and low potential (AZ31 alloy). CorrTech's extruded anodes are typically suitable for all kinds of water heaters and water storage tanks, or in pre polarization of offshore structure etc.