This is a wireless portable PA (Public Address) system with built-in DVD player and 2-channel wireless microphone, Model # Hisonic MVP2009. It is an invaluable tool for teaching, presentation and public speaking. It can be used both indoor, such as conference rooms, meeting rooms or auditoriums, and outdoor for an audience of up to 500 people. For indoor use, use the power cord and simply plug it into a wall outlet; for outdoor use, the system runs on two pieces of 12V/5AH Lead-Acid rechargeable batteries, which can last well over 8 hours. This system has a built-in DVD player which supports a variety of formats including DVD, CD, CD-G (Karaoke), CD-R, MP3 and even Kodak Picture CD, five different video outputs are available and they are Standard RCA video, S-output, VGA, YUV high luminance chromatics component output and 3-wire composite output (A.K.A. Pr, Pb, Py output). A fully-featured remote control and two pieces of AA batteries are included. Better yet, this system also comes with a built-in 2-channel VHF wireless microphone receiver, one channel is designated for a handheld Microphone, the other is for either a headset or a lapel, all the microphones are included. The transmission range can be as far as 300 feet. For your convenience, there are two additional audio inputs (standard 1/4") that can be hooked up with either wired or wireless microphones. The speaker system is composed of one 70 watts amplifier, one 8" woofer and one 3 1/2" tweeter for clear, powerful sound. Rugged corner-mounted casters and extendible luggage handle are included, self-assembly required, all you need is a screw driver and it takes about two minutes). It also has a built-in tripod mount.