The Beach Vault is a contraption that allows you to safely hide away your personal belongings in the beach if you feel the need to go for a swim, go for the bathroom or do anything that requries you to leave your belongings behind. Sure you could just use a backpack, but leaving a backpack in plain sight -- especially on a beach that's particularly crowded -- may not be a good idea if there are petty thieves roaming around.
So rather than leaving your valuables unguarded in a backpack on a sand, why not just bury them where nobody can see them? That's what the Beach Vault lets you do. It's a cylinder-shaped plastic container that is large enough to store objects such as tablets and e-readers. It is screwed into the sand and hidden under an attached towel.