The caches I have placed in Callan are designed to be found. This one is no exception but it is more difficult than any of the 'Magnetic' Series.
Getting to it, unless you park at the suggested site, will bring you along an attractive path from Callan town. If you tried 'Nearly Redundant' (GCBB405) on the way here you'll have a good idea what you are looking for.
The cache is above head height and you may require Tools of The Trade (TOTT) to retrieve it (depends on your height).
A hint - aimed at those relatively new to Geocaching - makes it easier if needed.
Good luck.