Phase Technology CI6.1X MP Ceiing Speaker Master PackPhaseTech CI6. 1X Ceiling Speaker Master Pack (4 Units) 6. 5 inch 2 Way In Ceiling Speaker with Micro Flange Grille. Designed and engineered for versatility, the CI6. 1X delivers high end sonic performance for either home theater or stereo music applications. The versatile variable axis tweeter allows the high frequencies to be directed to the listener in those situations where placement is less than optimal. All CI X models feature micro flange