Two tools that can appear similar, but that also have very different purposes are die grinders and angle grinders. See the detailed comparison between these tools here at FinePowerTools.com.
In this tool vs tool comparison, you can see the difference between the two popular rotary tools. Do you need a die grinder or a Dremel tool, which one is best for your work?
Die grinders 101. This ultimate guide explains what are doe grinders, how they work, what are the uses of this power tool. Learn everything you need to know about die grinder here.