May I ask what they actually contain ...or will?
Must be ultra expensive if they are that accurate.They take a battery, and a gps chip /aerial.
The round bits are the main body, the fan is all the lids nested.
They are for tracking rock movements.
So holes are core drilled into rocks / boulders, trackers are inserted, blanking cap and then resin sealed on top.
Then the movement of rocks in landslides / rivers / coast etc can be accurately datalogged
Must be ultra expensive if they are that accurate.
I have been looking for a sensibly priced thin GPS unit to fit into tube. I also need a 2g phone sim installed . But can't find anything.