Altimeter watches have in recent years become a must have tool when out walking.  Suunto have firmly established themselves as one of the leaders in the manufacturers of altimeter watches with the recent release of the Suunto Core range.   Altimeter watches are used to assist navigation when out climbing.  In order to get going with a Suunto Core black and green altimeter watch you first need to set your watch at a known altitude reference point at the start of each day, ie set the altimeter reading on your Suunto Core where you know the exact altitude. For maximum accuracy ideally reset the watch several times during the day at other known reference points along your route, as any changes in altitude and changes in weather will affect the accuracy of your readings.