SureFire Z41 switch upgrades

SureFire Z41 Switch Upgrades


The SureFire Z41 tailcap has been around for quite a while.  For more than 25 years this classic design has remained largely unchanged, even as handheld lighting has evolved immensely.  Inside its aluminum or Nitrolon shell, the Z41 houses a ruggedly simple switch mechanism that has proven itself to be durable, reliable, and ideally suited for tactical use.  With a simple user interface that allows momentary operation with a press of the tailcap, the Z41 ensures the flashlight is easy to activate when needed and, equally important, turns off when the switch is released.  Constant operation is achieved by simply twisting (tightening) the tailcap.

Although the Z41, along with its many derivatives, works well for its intended purpose, it’s not perfect for every application.  Some would prefer the convenience of a click-type tail switch while others may wish for a lower-profile or more efficient alternative.  Whatever the case, the popularity of SureFire flashlights has led to the creation of several aftermarket solutions allowing the Z41 switch mechanism to be replaced using only simple hand tools.

SureFire Z41 – Disassembly

These steps will apply to stock SureFire tailcaps equipped with tactical switches:

  • SureFire P-series (6P, 9P, 6PX, P2X, P3X, P2ZX)
  • SureFire C-series (C2, C3)
  • SureFire G-series (G2, G3, G2X, G2ZX)
  • SureFire Z-series (Z2, Z3, Z2X)

They will not apply to factory click-type switches and tailcaps or some of the oldest SureFire tailcaps.  These older tailcaps are easy to recognize as the switch mechanism will simply drop out on its own when the tailcap is removed from the light.

The first step in the upgrade process is disassembling the stock tailcap switch.  Dan Patnode has put together the best how-to tutorial (complete with photos) which can be viewed on the OVEREADY website.  (Note:  Installation of the Zero Resistance Twisty does not require full disassembly of the stock tailcap.  See below)

Once the tear-down is complete there will be several parts left over.  These may be saved so that the tailcap can be restored to its original state or, depending upon the upgrade path, some may be reused.

SureFire tailcap disassembly


SureFire Z41 – Upgrades

All of the upgrades described below are based upon parts purchased from OVEREADY.  If any of the components look worn or dirty, it is because these have actually been installed and in use on several of my personal flashlights.  All of the upgrades have parts made of brass which are very clean and shiny when new but begin to develop a patina with use.

TorchLAB McClicky Self Installation Kit

Don McLeish was one of the first to create a switch upgrade for SureFire flashlights.  Dubbed the “McClicky” his original design was intended for use with older E-series lights but was soon adapted for use in larger tailcaps such as the Z41.  The TorchLAB McClicky Kit comes with the McClicky switch, a brass adapter collar, and a new switch boot.  This particular upgrade will not reuse any of the original parts from the SureFire switch.

SureFire Z41 Switch Upgrade

Three types of switch boots are available, each requiring different amounts of pressure to activate the switch – Soft Press (available in several different colors), Medium Press, and Hard Press.  My personal preference is the Medium Press boot as it strikes a nice balance between ease of operation and prevention of accidental activation.

Assembly consists of placing the new boot into the tailcap, inserting the McClicky into the brass collar, and then screwing the collar into place using a pair of needle-nosed pliers.  Installation takes less than a minute and the finished product looks nearly the same as the stock Z41 tailcap.  Although the switch boot protrudes slightly farther on the McClicky equipped tailcap, the overall length of the flashlight remains nearly the same due to the tailcap always being fully tightened. (Click images for larger version)

The McClicky is a forward-click style switch meaning it provides momentary operation with a partial press and constant-on operation with a full press (and click) of the switch.

McClicky Pros

  • Designed around the proven McClicky switch
  • More convenient access to constant-on operation
  • Well suited for multi-mode lights that require a series of button presses to access different modes
  • Good current handling ability (better than stock SureFire click-type switches)
  • Various switch boot options

McClicky Cons

  • Not suitable for extremely high current loads (greater than 5A).  This should only affect ultra-high output LEDs in low voltage applications.

TorchLAB Zero Resistance Twisty

The TorchLAB Zero Resistance Twisty, or Zero Rez Twisty for short, is a solid chunk of brass that replaces the original electrical components in the switch.  As its name implies, the Zero Rez Twisty is intended to provide the lowest possible resistance and maximize output from the most powerful LEDs.  The stock switch only needs to be partially disassembled for this upgrade with the spring, aluminum cup, and rivet being the only parts removed.

TorchLAB Zero Rez Twisty upgrade for SureFire Z41

Retaining collar, plunger, and switch boot shown for reference only. These parts do not have to be removed for this upgrade.

Installation consists of dropping the brass Zero Rez Twisty into the tailcap and securing it by tapping the original rivet back into place.  Externally the upgraded tailcap is indistinguishable from the stock version.

Once installed, the Zero Rez Twisty functions the same as the stock switch mechanism providing momentary operation with a press and constant operation by twisting (tightening) the tailcap.  Since there is no longer a spring at the tailcap, the switch is deactivated by spring pressure from the head of the flashlight.  As a result, the battery must be able to move freely in the battery compartment.

Zero Rez Twisty Pros

  • Stock appearance
  • Same operation as the original switch
  • Low resistance and virtually unlimited current handling

Zero Rez Twisty Cons

  • Requires a good spring at the head to deactivate the switch.  May not work well with all drop-in LED assemblies.
  • Fitment must be checked carefully after installation to ensure battery is not crushed when tailcap is fully tightened.

TorchLAB Zero Resistance Mounty

The Zero Rez Mounty is an interesting design that replaces the entire stock switch assembly with a solid brass plug.  This allows the Mounty to provide two things the previous upgrades don’t – a perfectly flat tailcap and a 1/4″ threaded tripod socket.  The Zero Rez Mounty comes with an O-ring to provide a water-tight seal.

TorchLAB Zero Rez Mounty upgrade for Z41 tailcap

The O-ring is placed into the tailcap first and the Zero Rez Mounty is then tightened against it using a 1/2″ or 13mm socket.  Since there is no switch boot the resulting assembly is more compact than the stock tailcap.

The tripod socket is completely isolated from the interior of the flashlight.  Measuring 17mm deep it can be mated with any 1/4″ tripod or accessory.  With the wealth of camera related gear that uses this format, this introduces lots of options for carrying, positioning, or using the light.

After this upgrade the light operates solely as a “twisty” and is activated by tightening the tailcap.

Zero Rez Mounty Pros

  • Low resistance and virtually unlimited current handling
  • More water resistant than stock switch
  • Flat tailcap allows tail standing
  • Tripod socket allows light to be used with 1/4″ threaded accessories

Zero Rez Mounty Cons

  • Gives up momentary operation
  • Fitment must be checked carefully after installation to ensure battery is not being crushed when tailcap is fully tightened.

TorchLAB Zero Resistance Shorty

Like the Zero Rez Mounty, the Zero Rez Shorty is made entirely of brass and completely replaces the stock switch assembly.  However, unlike any of the other options, the Shorty allows the battery to protrude into the tailcap, effectively adding 15mm to the length of the flashlight’s battery compartment.  Use of the Zero Rez Shorty requires careful body selection to ensure the finished product will fit standard battery sizes.

Zero Rez Shorty upgrade for SureFire Z41 tailcap

After the included O-ring is placed into the tailcap the Zero Rez Shorty is tightened against it using a pair of needle-nosed pliers.  As with the Zero Rez Mounty, the completed tailcap is more compact than the stock version.

The added space in the tailcap allows the use of larger (longer) batteries than would normally be used in a given flashlight body.  As an example, the Zero Rez Shorty would allow a light designed to hold an 18500 (50mm long battery) to fit a longer 18650 (65mm long battery).  Also, by taking advantage of custom bodies like the 20mm Moddoolar TL20, the overall light length can be reduced while using the same battery.

With the Zero Rez Shorty, the light is converted to “twisty” only operation and is activated by tightening the tailcap.

Zero Rez Shorty Pros

  • Low resistance and virtually unlimited current handling
  • More water resistant than stock switch
  • Flat tailcap allows tail standing
  • Allows use of a longer battery or a shorter overall length with some flashlight bodies

Zero Rez Shorty Cons

  • Gives up momentary operation
  • Fitment must be checked carefully after installation to ensure battery is not being crushed when tailcap is fully tightened
  • Can only be used in certain configurations which will allow use of standard battery sizes

Final Thoughts

Short of installing a complete new tailcap these modifications are the easiest way to change the functionality of the SureFire Z41 tailcap.

Switch upgrades for SureFire Z41 tailcap

Each of the upgrades is reversible and, if needs change, easily converted from one to another.  Additional information about the upgrade process and parts can be found on the OVEREADY website:

The TorchLAB McClicky kit is assembled with parts from the USA and China.  All of the Zero Rez switches are 100% designed and made in the USA. is an Amazon affiliate site and stands to earn a small commission on purchases made after using any of the Amazon links on this site.  These commissions help support the site at no additional cost to the customer and apply to any purchases, not just for specific product links.  If you’re an Amazon customer and would like to support FlashlightGuide, be sure to check out what’s available at

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One Comment

  1. Zero Res Shorty is a fantastic momentary for me. Turn cap until it goes on then back off a little. Press on tailcap or pull back on bezel. I use it all the time.

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