THE UNIQUE ULTRACOMPACT X-RAY BINARY (UCXB) 4U 1626-67 IS THE ONLY KNOWN UCXB HOSTING A STRONGLY-MAGNETIZED SLOWLY-ROTATING ACCRETING NEUTRON STAR. THIS SYSTEM HAS A PLETHORA OF INTERESTING PROPERTIES WITH A SHORT (~42 MIN) ORBITAL PERIOD STRONG AND DISKBROADENED EMISSION LINES OF NEON AND OXYGEN AN UNUSUALLY WEAK AND POSSIBLY VARIABLE IRON FLUORESCENCE LINE A CYCLOTRON RESONANCE SCATTERING FEATURE (CRSF) AND VARIABILITY ON SHORT AND LONG TIMESCALES. THE X-RAY VARIABILITY IN PARTICULAR IS ESSENTIAL BOTH FOR PROPER INTERPRETATION OF THE SPECTRAL LINES AND FOR CONSTRAINING THE BINARY ORBIT. WE ARE REQUESTING A 40 KS NICER OBSERVATION WHICH WILL GIVE US THE OPPORTUNITY TO CARRY OUT THE MOST DETAILED STUDY OF VARIABILITY TO DATE IN THIS SOURCE.