A beam its more of a roman column of thick light. Its hard to even describe the beam. On the T40CS it has enough spill to illuminate everything immediately infront of you for over 30 feet, then the solid beam makes everything else just Too bright for 500 yards its been tested by pros on other forums and it meets or exceeds the manufacturers claims, and they tested the early version with just 788 lumens and a XML T6 emitter, mine was made a month or two ago using the Premium XML U2 emitter better color beam and 845 Lumens.
On the Klarus XT11 still has nice beam but no where near the T40CS, I got the T40CS because it is smaller then my old 2 D cell MagLite that I carried everywhere.
Only problem with these two is at 600 Lumens and 845 Lumens do not use them indoors at night, you will blind yourself. Also the strobe on the Klarus XT 11 is randomized it will disorient and wild dog or animal immediately.
I have a cheap Fenix E21 150 Lumens uses two AA and that what I use everyday by my bed.