TorchLAB ZeroRez Shorty Z41 Brass Insert (twisty+15mm)

TorchLAB ZeroRez Shorty Z41 Brass Insert (twisty+15mm)

Product Information

Zero Resistance Shorty Z41 Brass Insert

Like the original ZeroRez, the Zero Rez Shorty is carved from solid brass (no spring), allowing more energy to travel from your battery to your LED or bulbs than any spring equiped clicky or twisty configuration. 

But the Shorty takes things a step further.  Doing away with all springs, switches, and boots, the ZR Shorty "adds" battery tube length to anything into which it is installed.  So you give up all click and momentary functions and gain either 15mm more in battery length or 15mm less in flashlight length.  As this leaves the end of the tailcap flat, tailstanding is also possible.

  • Greater simplicity and reliability than any other part or configuration
  • Preassure seal with O ring keeps out water
  • Run a 35mm cell in a 20mm long tube (like the Brass Shorty)
  • Run a 50mm cell in a 35mm long tube (like an 18500 in a TL35)
  • Run a 65mm cell in a 50mm long tube (like an 18650 in a TL50)
  • Run two 18650's in a 115mm tube (like a bored 6P with a bored A14)
  • Upgraded and now compatible with CR123's


The ZRS is comptaible with 18mm (bored) and 17mm (unbored) alike, but is not for use with:

  • 65mm long bodies, including TL65/6P/C2/Z2 (there are no 80mm cells)
  • 100mm long bodies, including TL100/9P/C3/Z3 (there are no 115mm cells)
  • 130mm long bodies, including TL130/M4 (there are no 145mm cells)



Want the ultra simplicty of the ZeroRez Shorty without extending your setup?  Add a 15mm Delrin Spacer to delete your momentary button/boot while also 'canceling out' the extra length.  


The Idea:

A way to think of it is electricity and wires is like water traveling through a pipe to move a wheel. Volts is the pressure the water is under (force), amps is the size of the pipe (quantity of water), and watts is how much work winds up getting done, how much the wheel turns when the water hits it (power).  LED(s) need a certain amount of watts/water. If you lower the volts by running on a single cell (smaller pipe), the only way to deliver the same amount of energy (watts/water) is by boosting the pressure/amps (water goes faster). But if you don't upgrade the pipes, they can't handle the extra pressure. So to with springs and switches. Lower the voltages and they either slow down the current or burst in the process.

Our Zero Res upgrades are ideal for low voltage, high amperage setups. If you are running a high voltage setup (12v), the amps don't need to be as high to get the same watts. The McClicky is good up to about 5 amps. The Z41 twisty will not blow until well above 5 amps, but it will start retarding energy flow (resistance) well before that.
The ZRS is good to over 20 amps.



Like our McClicky kit, the ZRS can be installed in all Z41 & compatible tailcaps, including the Moddoolar Triad.

Follow the instructions for our McClicky installation, but thread in the ZRS brass ring in place of the McClicky brass ring.

For a water tight seal, the included O ring goes above the ZRS and should be placed into the empty tailcap before threading in the ZRS brass disc.

Swapping between the ZRS and our McClicky kit on the same tailcap takes only a minute and can be changed at will with simple tools.



  • Test battery fitment carefully the first time that you use this tail mod. Screw cap on slowly to be sure that you do not crush your cells.
  • As this lacks any spring, switch deactivation force now comes from above your battery.  Smooth battery movement inside the flashlight body is vital.
  • This mod will deliver all of the current to your drop-in that is available.
  • Use care when lighting up your direct drive setups.

This item is made in

Design & Engineering   Tom
Machining - Craig
QC & Logistics
- Dan


Product Code: OR-ZRShort

In Stock: 45

Quantity: Add to Basket

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