The Aquapac pouch is designed to hold the YB3 tracker.

For very wet watersports, this is ideal. While the YB3 is IP-67 rated, if you expect to submerge the YB3 in water continually, you should put it in one of our custom-designed Aquapacs.
 
The Aquapac comes with an armband strap, which can also be used to secure it to a rucksack, and you can use the buttons and see the screen through the clear plastic

NOTE: to use the alert button, you would need to remove the unit from the Aquapac, as you have to lift the alert plastic cover.