Just so anyone looking at this knows, if you take it off after giving yourself Phalanx with it, the Phalanx effect immediately drops.
Dmg reduction of about 17 sounds right, lasts 3 mins, recast is 10 mins, and the actual activation time is a bit long.
I can definatly see some uses for this, and since it's got 50 charges, you've got some time to fool around with it.