A small double-ended magnetic tube. A final, physical cache at the end of the Cheltenham Cavalcade Adventure
Once you have solved the five stages of the Adventure Cache "Cheltenham Cavalcade" you will have the answers you need for this final bonus. These answers can be found in your journal entries.
The final is at N51 53.ABC w002 04.DEB
(20/9/2020 Final co-ordinates moved just a little to get the right side of the water. Checker changed)