While cleaning out the old Ford Explorer, I found the "instructions" for an old Deben Mark I locator collar, of the type I still use. Back when Deben was dropping the old Mark I for the new Mark II, I was pretty sure the new collar was not going to cut it, and and I bought a second old locator box and a pair of new collars to go with it. I was right! The Mark II collar was eventually kicked to the curb for the Deben LRT locator, which is sold at about twice the price of the old bit of kit.
These Deben Mark I instructions may be older than the car I just traded in, as I kept the two Mark I collars I bought in their original packaging for several years until I actually had four dogs on the ground and in the field, at least two of which were not my own so I had to equip folks who had nothing to put on their dogs . I post the old Mark I Deben package insert here, for historical purposes, as package inserts are always the first to go!
All my old Deben Mark I collars are going fine, by the way, as I customize them a bit with an o-ring and epoxy.