This anti-tank block is situated some 230m from the A5, on the Ogwen Pass, a strategically important route between Bethesda and Capel Curig. It is adjacent to a mortar emplacement (NPRN 270451) forms part of the Scheduled Ancient Monument, Nant Ffrancon anti-invasion defences, dating to the early period of the Second World War. It is reportedly incomplete, but originally comprised eight anti-tank blocks made of stone and is adjacent to a spigot mortar base.

Sources include:
Defence of Britain Project (Record Number 7464)

RCAHMW, 22 January 2014