X-Ray Vision is a vision based power enabling an individual the ability to see through virtually any known surface.
X-Ray Vision gives one the ability to see through virtually any known substance, be it metal, wood, stone, crystal, etc. A power such as this gives one an edge in terms of locating people or items hidden away in cases, safes, even underground. Some individuals have also utilized this for finding people underwater, as well as for medical purposes for those who have been injured.
The most notable limitation to the ability however is that most users cannot see through anything that is lead-lined or composed entirely of lead.