In order to guard the Tefillin against damage that is liable to render them unfit, they must be carefully protected from moisture and heat. Moisture is liable to mar the passages and the writing, and heat may harm the color of the Tefillin.
It is strongly recommended not putting the hand Tefillin on a sweaty arm, or the head Tefillin on a wet head.
Care must be taken when removing the Tefillin from their case, in order to pray, and when returning them, so that the corners of the batim will not receive any blows.
"Oter Israel"`s Maginit provides optimal protection for your Tefillin. The Maginit (from the word magen, protection) guards Tefillin against moisture and blows. It is highly recommended that everyone keep their Tefillin in a Maginit. Such protection is especially important while traveling or hiking, for people who are accustomed to keep their Tefillin in their automobile, and for soldiers.