So I found this multi-tool thing in my drawer, recently, which has:
- A magnifying glass, allowed on-board, I think.
- A compass, also OK.
- and a thermometer, not OK.
However, the thermometer is covered in plastic very tightly and the liquid is red (mercury isn't red, is it?), so would that be OK on a plane? I don't need it, I am just curious if it is allowed and if there is anything I can do...