Unknown Security Fastener Screw - which Version is this (similar to System ZERO) ?

Explanation of "SYSTEM ZERO" is here:

I am looking for the right naming of the screws from image No 1-3 so as the suited bit from image No 4 (on left).
Image No 5 shows a slightly variation of this kind of screw (also on left).

System ZERO looks like the images No 6-8 (screwdriver-kit, bit and screw)

Such an screwdriver-kit I want to have for the screws showed in image No 1-3.

Thank you for an information.


  • Unknown Screw-1.jpg
    Unknown Screw-1.jpg
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  • Unknown Screw-2.jpg
    Unknown Screw-2.jpg
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  • Unknown Screw-3.jpg
    Unknown Screw-3.jpg
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  • appropriate bit for image 1-3.jpg
    appropriate bit for image 1-3.jpg
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  • Unknown screw different - on left.jpg
    Unknown screw different - on left.jpg
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  • System Zero Screwdriver kit.jpg
    System Zero Screwdriver kit.jpg
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  • System Zero DLH4-125 bit.jpg
    System Zero DLH4-125 bit.jpg
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  • system zero screw.jpg
    system zero screw.jpg
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Search for "security screw head", all shall be revealed. E

It could be a T-Groove (also known as tri-groove) tamper proof screw ?
Thank you for both information.
All versions on the web are according image No 5 from post #1 - go to
M8-1.25 T-Groove Tamper Proof Security Nuts x 4 & Tool Socket Stainless Tri 8mm | eBay
TGroove, Tri-Groove, Tampruf - Loss Prevention Fasteners
T-Groove Button Machine Screw - Tamperproof Security Fasteners | SUPERFASTENER
Maybe the screws in question are special small versions of those with very small outer diameter of necessary nut driver socket due to the deep countersinking of the screw head.
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