I have to replace several light units that are secured with this type of screw. I assume this is a type of tamper resistant screw. Can anyone tell me what it is called?

mystery screw

  • 2
    Is that actually the head of a screw, or is that the hole it would go into? If it's the hole then it looks to me like a quarter-turn kind of thing.
    – brhans
    Mar 29, 2017 at 14:33
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    both Amazon and widgets.com sell, or used to, large sets of funky bits and security bits. Shop around and you may find a (much better) photo of a bit that matches what you've got. Your photo is not very good, sadly. Mar 29, 2017 at 19:55
  • @brhans Sorry about the poor photo, its the head of the screw. It's like a male clutch screw head if that's a thing
    – Nic
    Mar 29, 2017 at 20:10

1 Answer 1


Security Screw Diagram My guess is that this is a Clutch type screw. (First row, sixth column)

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