I recently replaced the standard tailcap on my Surefire 6P with their model Z49 click-on lock-out tailcap, which has a two position thumb switch. Press the switch once for momentary "on" mode, press again until you hear an audible "click" for constant "on" mode. The constant "on" mode with the standard tailcap requires two hands to operate (to twist the tailcap).
The Z49 tailcap adds about 3/4 inch to the overall length of the 6P light. It also has a rubber grommet around the thumb switch to prevent accidental activation.
A disadvantage for some users is the fact that the tailcap body is slightly larger in diameter than the flashlight's barrel, so with the Z49 tailcap in place, the light can't be carried in standard holders. This is not a problem for me, since I carry my 6P in a GALCO holder. (Reviewed in a previous post). In fact, I now have two carry options, lens up or lens down.
The Z49 tailcap adds about 3/4 inch to the overall length of the 6P light. It also has a rubber grommet around the thumb switch to prevent accidental activation.
A disadvantage for some users is the fact that the tailcap body is slightly larger in diameter than the flashlight's barrel, so with the Z49 tailcap in place, the light can't be carried in standard holders. This is not a problem for me, since I carry my 6P in a GALCO holder. (Reviewed in a previous post). In fact, I now have two carry options, lens up or lens down.