One of a series of technology caches in Hamilton If you enjoy this one, then have a look at GC1PRKD and GC13MVW
Invented by Ericsson, and named after the king Harald Blåtand, this is all around us these days. An august body of engineers knows it by a number, you need find this and to use the digits ABC.DE.F to decode waypoint 1. When researching, you might also find Harald's companions, so ignore anything Oracular or PC-ish; the name you want really is simple!
At WP1 you need to use some special equipment with Harald’s namesake, and enquire from him the location of the final. If you can’t get him to show the details, try sending him something.
At the final you are looking for a 2litre click-clack box, and you don’t need to go on any private property at any point during your mission.
Waypoint 1 is at 37 49 ABC+72 175 17 DEF+389
As always, it is important you re-hide the box well
Radionut50 acknowledges Bear Left for the inspiration on this one.