WARRANTY Although MM is warranted for 2 years, we have calculated the lifetime of a MM to be somewhere in excess of 10 years. The custom internal battery is delivered straight from its own manufacturing line to our assembly line - the battery will physically decay before the MM runs out of power! If you do have a problem with a MM in the warranty period, just return it in undamaged and good condition to the store where you bought it. They will replace it free of charge and send your old unit back to us for examination. Warranty period is calculated as 2 years from the install date in the MM. If the install date fails to show, then proof of purchase must be produced. Our warranty is specifically limited to the replacement of a unit.