1. the cloaks would not sustain invisabliity for a long time 2. its using reflection and optical cloaking to contain the cloak itself 3. for recon during war and security guards to keep slient and stealthy

1.The compound is filled with a chemical that has twice the amount of oxygen pressure which allows you to breath in places with denser air such as underwater. 2. Because when you get deeper into the water the temperature becomes ice cold so sine their is no heat, you would not be able to release the chemical allowing you to breathe. 3.The reason the crystal is not available is because the fact that they have not finished trials and their for it has not been proven safe.