If you decided to buy crystals for any purpose you should know that you can program your crystal and make it work for your intention. If you bought crystal with the aim of protection you can ask the crystal to protect you and its power will be focused on realizing your intention. It does not mean that you give crystal power you simply make its energy to be directed on your aim.
Some people born having good developed Astral Bridge Layer because in past lives they have developed it. As such even if you are not a psychic now, it is possible to develop your Astral Bridge Layer with the help of meditation and strong ability to elicit your inner power in this incarnation.