Fine active hybrid soundhole pickup and high performance "mems" microphone with two separate volume controls, rechargeable preamp and Mi-Si power charger. No batteries needed. A 60 second charge allows for up to 8 hours of performance. This is a magnetic "planar" single coil pickup and "mems" microphone, designed to minimize hum while providing a broad frequency response. Black housing, easily clamps in soundhole, mini-jack in pickup allows you to use a patch cord externally or easily connect internally to a 1/4" strap button jack harness (included). Pickup measures 3" across between the clamp, so soundhole needs to be a tad bigger than 3" diameter in order to install it. A simple effective system for acoustic guitars.