25x GPS ankle trackers

I would like 25 durable (they couldn't break it even if they use a chainsaw or pliers or extreme heat and cold of some sort), waterproof (fully submerged for 12 hours at the least) and discreet (Doesn't look like an ankle monitor) ankle bracelet trackers that track anywhere in the world even underground or on a plane. I would like them to only be taken off with a key or code of some sort (I want to be the only one to be able to take the trackers off). They need to be breathable and comfortable for babies - teenagers (boy and girls). I also want to know who is who on each tracker (Where each person is at by name on the tracker). I don't want it to have any dead zones. I want to be able to track them anywhere in the world at anytime Even underground if need be. Plus I don't want anyone to be able to hack into their location. The battery should also last up to a week or more on one charge. THIS BIO IS BOUND TO CHANGE AT ANYTIME, CHECK WITH ME FOR ANY UPDATES