Quote Originally Posted by The Vorpal Tribble
Psicrowns are the psionic equivalent of a staff, yup. And it says Manifester Level 11, so these powers can be manifested as an 11th level manifester.
(SRD material)

Unlike with other sorts of psionic items, the wearer can use his manifester level when activating the power of a psicrown if itís higher than the manifester level of the psicrown.