mouse34Btn lets you use your 3-th and 4-th mouse buttons to Copy (Cmd+C) and Paste (Cmd+V) in all applications that support these commands. It’s very lightweight and is meant to replace Logitech Control Center (LCC) or BetterTouchTool which otherwise are good apps, but are too complex and heavy. If you just want to copy and paste with your 5-button mouse, then mouse34Btn is for you. If you're X-Mouse Button Control user on Windows (XMBC) and you're looking for a Mac alternative, then you’re in the right place. Pros: mouse34Btn is a very lightweight application. It doesn’t install kernel extensions (that may crash your system), open network ports, connect the Internet or write any files on your HDD. All apps that intercept your keyboard (e.g., LCC, BetterTouchTool) must be approved as assistive devices in system preferences. mouse34Btn as a mouse-only app doesn’t require this. mouse34Btn is an open-source project, so you can examine or modify the code. Applications that intercept or log keyboard and mouse events raise security concerns, and it’s good to examine their work. Cons: mouse34Btn has no preferences, so you need to recompile it if you want different than copy and paste actions.