The good thing nowadays is that airsoft players get to have more choices now in tracer units to use for night operations. Mach Sakai checks how the Xcortech XT501 MK2 Ultra Bright UV Tracer Unit. This unit is powered by 4 Triple A Batteries that can last up 120,000 rounds. UV-LED Illumination is adjustable and can keep up to 35 rounds per second.