I have used several models of Mighty Bright book lights for years, daily and for travel, and this one is the best.  It's the brightest, and the wider 6-LED head illuminates a whole page of a hardcover book and both pages of a small paperback.  It has 2 brightness settings controlled by the on/off button on the head (though I don't find much of a difference in the 2 settings).  The button is easier and quicker to use than the slider switch on my others.  It goes through batteries faster than the smaller-head lights with fewer LEDs, but I use rechargeables so it's not a problem for me.