Mentimeter is entirely browser-based, meaning that your audience can use any internet-connected device to interact and vote during your presentations. The most common case is to use a smartphone, and here are the general requirements:
Android: version 4.0 or later
Windows Phone: version 8.0 or later
iPhone: iOS 7.0 or later
Please note that cookies need to be enabled on the voting device. This is managed through the browser settings.