3e SRD:Hide Power
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Hide Power [Metapsionic]
Benefit: A psionic power can be manifested without one associated display characteristic chosen by the character when he or she takes the feat: auditory, material, mental, olfactory, or visual. The hidden power costs a number of power points equal to the standard cost +2.
Special: A character can take this feat multiple times, each time choosing a different display characteristic to hide while manifesting a given power.