This our MRCE1EZPK6 which uses zinc materials. For aluminum please review MRCE1EAPK6. Offered is a 1.5" 6 pack of full anode assemblies which includes the brass holder and anode. This is the easiest way to replace the anode for your heat exchanger. this is for a 3/8" NPT thread size and will be a drop in replacement for a heat exchanger that has that size anode fitting. These parts will replace any 1.5" E1E product or you can cut it to length if it is shorter. Anodes may not be returned so be careful when ordering.