some people have degrees, other people have common sense and dont have to be told theyre smart -_-...its steel.
ive left the seatpost in the shop but its small, not oversize, 27.6 or so is what im measuring. i think the seatpost must have been 27.8 because it was shoved in!
Magnets.
Though I'd plump for steel, looking at the rear brake bridge.
What size seat post does it take?