The Lil'DMXter is a portable test set for checking DMX512 transmission and reception. It is also a cable tester for DMX512 cables, testing both continuity and data transmission. The unit is built into a water-resistent case. It's pretty rugged - but the display is glass so please use reasonable common sense care. The Lil'DMXter is battery operated using rechargeable batteries. We ship it with a good charge, but you may want to plug it in overnight to top it off. Use the line cord provided to connect to a 120VAC outlet. The Lil'DMXter will run while plugged in as well.