Q: TC4 tail-cap does not seem to be working properly.

A: There are several possible reasons that the TC4 tail-cap switch may not be working properly. Please go over the following checklist carefully: Remove the TC4 tail-cap completely from the light. Make sure the batteries are inserted according to the orientation per operator manual. Place the tail-cap back on. The TC4 tail-cap has safety lock mode which means the light will not switch on even if the tail button is pressed. This mode prevents accidental switch on. To be sure that the switch is not placed in safety lockout mode, turn the tail-cap down as far as possible then attempt to switch on the light by pressing th tail button. Our tail-caps are built with heavy duty switches and operatable through tough rubber buttons. Compared to other tail-cap switches in the market today, you will experience higher quality feel and will require more pushing than those other ordinary tail button switches. This provides you with greater control between momentary and constant on. TC4 is preferred by law enforcement community exactly for this reason. Our TC4 tail-cap has modulated throw. This means depending on how far the tail-cap has been screwed down, the amount of push on the tail button needed will vary. Try positioning the tail-cap at different depth into the thread and try the tail button switch. If you are still experiencing difficulties, please contact our customer service department.