MMI Altitude

[bod01]

Bit of a odd question this one. Trailed a boat down to Lake Garda the other day, absolute dream behind the car. When going through the mountains notice that when the altitude got to a 1000 meters a small M showed on the MMI screen next to the image of the mountains. Couldn't see any mention of it in the manual and was just wondering if anything appears if you go below sea level like a U for underwater! Sad one I know but it is a 13 hour drive so you have a bit of time on your hands.

[@mark]

Living out on the Fens much of my time is spent at sea level or below

Can't say I have ever noticed anything when the reading goes into minus figures.