This kind of anode screws into the hot-water port and can either replace another combo rod or augment a hex-head anode. Fits all residential water heaters with 3/4-inch plumbing.

• The anode will keep your tank from rusting and breaking.
• The dip tube and drain assembly control sediment buildup by forcing water and sediment to swirl around the bottom of the tank and out.
• The ball valve has a relatively large diameter opening and a straight path, which make it harder for big sediment chunks to clog it, and easier to clear it if they do.
• The cap keeps the unwary from flooding the water heater space by accidentally opening the ball valve.
• The tape will make it easier to get the anode out to check its consumption down the road.
• The book will not only guide you to the installation of parts, but help you understand and resolve other water heater problems.
• The sticker will help you remember when you installed the parts.

• Pipe wrench
• adjustable pliers
• drill with 7/8-inch hole saw
• basin wrench
• hammer
• flat-bladed screwdriver.

A warning

If you buy one of these, don't play with it. These are regular anodes that have been milled down to the core wire on a lathe. That wire can be bent and straightened about three times, then it snaps.

The products offered here are designed to make water heaters last longer, or solve specific problems. Installation is potentially do-it-yourself, but if you have the least doubt about your abilities, we suggest that you obtain expert help.

Prices include ground shipping by UPS within the contiguous United States. UPS does not deliver to post boxes. Allow 2-3 weeks for shipping, but we usually ship within 24 hours. Hawaii and Alaska are only served by Second Day Air or Priority Mail. People in those states should e-mail to learn shipping costs. We do not ship outside the United States.

1. If you contemplate adding an anode to a new tank, make sure both rods are of the same metal. Otherwise, the magnesium rod will be consumed more rapidly in the presence of an aluminum one and you won't get as long a life. How do you tell them apart? An aluminum hex head will be flat on top, while a magnesium rod will have a bump, as in the photo above. The exception to that is Rheem and its sub-brands, Ruud/Richmond/General Electric. As far as we know, Rheem always uses magnesium even though there is no bump on top of its anodes. On the other hand, if the tank is five years old or more, having dissimilar metals is less of an issue, since the original one will likely be largely consumed. Also tell us the brand of your heater.

2. Measure your water heater from the top to the drain valve and send the measurement to us at info@waterheaterrescue.com. There are a few tanks that are shorter than average that require a shorter curved dip tube.

3. If you're getting a maximum-insulation tank, as we recommend, tell us so that we can include a 4-inch drain valve nipple.

Price: $125, shipping included. California residents add $9.06.