I have an older Fenix that is one level only and takes a single CR-123 battery, but they do not make them any more. I am pretty sure that no one makes a single level CR-123 light, since the multi-level lights are all the rage in the flashlight world.

The Olight i1 is very simple operations for a 3 level light, I am really content with mine and the lower levels are handy when you want to prolong battery life.