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The Conversion Gel

The Conversion Gel[2] is a testing element used in the Enrichment Center several decades before Portal, and appears in Portal 2. It is one of three types of Mobility Gels.


Conversion Gel is a white fluid that allows the Portal gun to place portals on surfaces that would normally be unfit for placing portals. A main use of this is in the end of Portal 2, where Chell used it to her advantage to defeat Wheatley. Several areas in the Condemned Testing Facility seem to indicate that the Conversion Gel was used to paint all further testing facilities, explaining how only white, painted walls were affected by the Portal Gun.

According to a pre-recorded message from Cave Johnson, the Conversion Gel is made up of ground-up Moon rocks, as they are an excellent portal-conducting surface, although contributing to Cave's death due to being poisonous.