The Ibanez Edge III is a double locking tremolo system developed and produced by Ibanez, introduced in 2005. Like the Edge Pro II and Lo TRS tremolos before it, the Edge III is made for mid-level priced Ibanez guitars usually made outside Japan. The Edge III is named after the original Edge and Edge II. Unfortunately many people complain that these trems do not function as they should.
Tip for trems not returning to a clean neutral position (returning mistuned whether pushed or pulled): Replace the screws to adjust the tremolo spring strength. This is normaly the last part which is under suspicion. Use more stable/longer screws which have better grip in the body.