Multitasker M4 Tool


The M:4 is a patent pending 1-piece multi-tool for the M4 carbine designed and manufactured by MultiTasker® in conjunction with B5 Systems, makers of the SOPMOD and SOPMOD-Bravo buttstocks. If you’ve purchased a B5 stock within the last year your buttpad should be compatible. Please double check. 

(2 customer reviews)

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The M:4 is precision machined from solid barstock using wire-EDM/CNC, and fits discreetly with no visible footprint inside a specially inletted buttpad made by B5. Easily accessible without tools simply by pressing the release tabs on the buttpad. Dot coded to indicate functions.


  • Hollow ground 3/8’ slotted screwdriver
  • Dual-lug M4 castle nut spanner wrench
  • 1/2“ hex wrench
  • Bolt override malfunction clearance tool
  • 420 stainless with Melonite® finish
  • Dimensions 4” x 0.5”
  • Weight Less than 2 oz

Additional information

Weight .1 lbs
Dimensions 6 × 4 in

2 reviews for Multitasker M4 Tool

  1. bryce.t.reynolds (verified owner)

    Super handy to have and love that it stows away out of sight in the B5 buttstock.

  2. fioricafirearms308 (verified owner)

    Very handy tool to be able to keep on-board your AR if using a B5 Systems stock. The tool was a bit smaller than I was expecting, but I was still able to use it just fine to tighten down the castle nut on my lower. Always nice to have tools that are easy to use and accessible, which this fits the bill perfectly. Doesn’t add any noticeable weight while still being made of durable materials and doesn’t impede function or add additional snag points, as it is stored in the recoil pad of the B5 Systems Enhanced SOPMOD stock that I purchased at the same time as this tool.

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