Virgilthere's a button on the tail end. Flush enough so you can tailstand on a flat surface without activating, but not so recessed that you can't easily push it on. I carry mine in my jeans "coin" pocket every day and I have never accidentally turned it on (unlike my older foursevens preon p1). In terms of ease of button press, It has always turned on when i expected it to in regular use.
l2yuk3nThanks for the info I will get one i have a lot of AAA lights but tend to like the clickies better for ease of use. My favorite is my copper Lumintop with rubber clickie but I like the fact you can stand this one on its end I have a copper Preon from foursevens and it has that copper clicky which just doesnt click right or feels off.