You essentially can't replace the front glass on your iPhone because it is glued to the screen itself, however, you can replace the back easily. You just need one screwdriver and it slides off. There are many back replacements that won't shatter including wood and aluminum backs however there isn't really a single shatter proof glass anywhere... If you want to shatterproof the front of the phone there is a new glass screen protector which should greatly increase its strength, and that coupled with say, an aluminum back would mostly shatterproof your phone