Buying the part yourself and installing it can save a lot of money! Search for a great deal online and you're more than likely going to find it. It's always good practice to check out the prices for a spare part for your Kidde RF-SM-DC from several different places. That way you can be sure you're getting the best deal. There are usually more than one company producing the Kidde battery operated wireless-inter-connectable smoke alarm part that you're looking for, especially aftermarket-type spare parts. Find the right part and fix it right!