I use Lookout and it works well. It doesn't use a lot of battery and runs quietly in the background. Now, I'm sure many of the next posts will be quick to tell you to just use common sense and that anti-virus protection isn't important. Common sense is an excellent defense, but given the rare occasion that that doesn't work and for those occasions when bad things have made their way into the Play Store, I like to err on the side of having a safety net.
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