Blarney Castle is one of Ireland's top tourist destinations. It contains the legendary Blarney Stone - kiss it and you'll never again be lost for words. Or as the locals put it you'll have the "gift of the gab". Kissing the stone involves hanging upside down from the top of the castle with someone holding on to you. It certainly gives you something to talk about.
This cache won't require that level of commitment! In fact keeping quiet might be an advantage as stealth will definitely be required.
It is a magnetic key box. BYOP.