Voice-activated recording is a convenience feature for hands-free recording. When enabled, recording will start automatically when you start speaking. Recording stops automatically after you stop speaking and restarts automatically when you start speaking again. Just plug your recorder into your PC and play in Windows and Mac OS. The large graphical display lets you view all important file information at a glance, even in poor lighting conditions, thanks to the backlit display. This voice recorder has 4 GB of memory built-in and is expandable via its Micro SD memory card slot. You have virtually unlimited recording capacity thanks to a micro SD memory card slot supporting up to 32 GB of additional memory. The batteries of the new recorder last for up to 42 hours for extra-long recording sessions.