Just as JetBeam redesigned the RRT-2 with an upgraded XML LED, they decided to do the same with the RRT-0 by creating the RRT-0 XML. The RRT-0 still has the ramping ring, allowing the user to create a custom lumen output and can cycle through modes easily with one hand. However, unlike its predecessor, the XML boosts the light’s lumen output from 255 to a staggering 550 lumens. But the best feature of the RRT-0 series is its ability to adapt to batteries: as an option, the user can add a AA extender to the light, which comes in handy for dire situations where CR123 batteries are not available.