I've driven past this stone a few times now on the way to the complexes in the same townland. It stands right at the side of the track that leads to them. It is 1.6m tall and very uneven. It is aligned northwest-southeast on its long axis and may point to the dome of rock at Scartnadrinnymountain.
A few metres away there is a Fogra protection sign, but it's hard to know exactly what it is marking. There are a couple low, circular structures that may be hut sites. This could be where the people who built the many monuments in the valley above lived.
This is an explanation of (and a bit of a disclaimer for) the coordinates I provide.
Where a GPS figure is given this is the master for all other coordinates. According to my Garmin these are quite accurate.
Where there is no GPS figure the 6 figure grid reference is master for the others. This may not be very accurate as it could have come from the OS maps and could have been read by eye. Consequently, all other cordinates are going to have inaccuracies.
The calculation of Longitude and Latitude uses an algorithm that is not 100% accurate. The long/lat figures are used as a basis for calculating the UTM & ITM coordinates. Consequently, UTM & ITM coordinates are slightly out.
UTM is a global coordinate system - Universal Transverse Mercator - that is at the core of the GPS system.
ITM is the new coordinate system - Irish Transverse Mercator - that is more accurate and more GPS friendly than the Irish Grid Reference system. This will be used on the next generation of Irish OS maps.