[fecal_henge]

I find some of these numbers hard to believe sometimes. 40 mm seems really big for a table tennis ball.

[a_shoeboy]

It's 0.00019884 furlongs, if that helps.

[nandomrumber]

Or 0.0008 OSP (Olympic Swimming Pools)

Edit to add: length, not volume

[Rooster61]

Or 0.000587613 smoots

https://en.wikipedia.org/wiki/Smoot