The Surefire Z32 bezel was used on the Surefire M2 flashlight and currently on the Surefire M951XM07 Millennium® Universal WeaponLight. The main design function of the bezel is to isolate the incandescent lamp assembly from weapon recoil shock. Since the shock mechanism reduces the heat dissipation ability of the bezel, I use aluminum shims or copper tape around the LED drop-ins to help dissipate the heat through the flashlight body.
The Surefire 6P, is to me, what a flashlight looks like (though I have moved on from incandescent lamp assemblies to LED drop-ins, such as this modified Malkoff M61). The stock Surefire 6P is 5.20″ (132 mm) long and the bezel diameter is 1.25″ (~32 mm). I like the current design of the Surefire Z32 bezel as opposed to the original design with the vented ribs. The Z32 bezel is about 1/4″ larger in diameter and about 3/8″ longer than the Z44 bezel that is standard on the 6P. With a Z32 bezel on a 6P body, it looks even more like a flashlight.