The most active feature of the pendant is to restrict Phred's strength so he doesn't go out of control. As a result, Phred's base strength is only a bit greater than he would be untransformed but the restrictions will lessen gradually as Phred needs it during battle.
Even though he mantains his mind, Phred is unable to use his electrical abilities, thus forcing him to rely on his increased agility to fight.
The pendant isn't perfect though, and it will fail if Phred is under signifigant duress.