I often find these metal cylinders in the streets of London: a silver-colored tube with a round tapering at one end and a hole with no thread at the other.

Top view of the metal cylinder Front view of the metal cylinder with hole

What are they?


1 Answer 1


These containers are nitrous oxide canisters



  • 1
    $\begingroup$ I would have guessed a CO2 cartridge used in a pellet gun, but a web search shows that it's more likely sniffers(?) debris from inhaling NO2. Thumbs up for Mr. D. Duck $\endgroup$
    – fred_dot_u
    Commented Apr 28, 2019 at 23:19

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