Only as a nitpick, they don't look like folding rulers to me, they seem like normal (non-folding) rod/staff of the kind often used in topography. It would be d

Only as a nitpick, they don't look like folding rulers to me, they seem like normal (non-folding) rod/staff of the kind often used in topography. It would be dangerous to point one of those at someone's nose, a wrong movement or an accidental push and an eye could be seriously harmed.