The Surefire U2 Ultra is a slight departure from Surefire’s normal philosophy of less is more. Instead of the one or two output levels of most Surefire lights, the U2 has six levels of output, giving you between 2 and 100 lumens for almost any lighting task. The modes are selected by twisting a ring below the head, similar to the JETBeam Raptor or Fenix TA lights. The action is silent though, unlike the JETBeam or Fenix models, so you can switch modes without alerting others in a tactical situation. Or, in my case, I can switch modes without having my dog hear, since he is a ninja stealth master.
Watch the U2 and its stealthiness: