The NGC 1333 IRAS 4B region is observed in the 6.9 mm and 1.3 cm continuum with an angular resolution of about 0.4 arcseconds. IRAS 4BI is detected in both bands, and BII is detected in the 6.9 mm continuum only. The 1.3 cm source of BI seems to be a disk-like flattened structure with a size of about 50 AU. IRAS 4BI does not show any sign of multiplicity. Examinations of archival infrared images show that the dominating emission feature in this region is a bright peak in the southern outflow driven by BI, corresponding to the molecular hydrogen emission source HL 9a. Both BI and BII are undetectable in the mid-IR bands. The upper limit on the far-IR flux of IRAS 4BII suggests that it may be a very low luminosity young stellar object.

NGC 1333 is a nearby star forming region, and IRAS 4A and IRAS 4BI are low-mass Class 0 protostars. IRAS 4A is a protobinary system. The NGC 1333 IRAS 4 region was observed in the 22 GHz water maser with a high resolution (0.08") using the Very Large Array. Two groups of masers were detected: one near A2 and the other near BI. Most of the masers associated with A2 are located very close (< 100 AU) to the radio continuum source. They may be associated with the circumstellar disk. Since no maser was detected near AI, the A2 disk is relatively more active than the Al disk. Most of the masers in the BI region are distributed along a straight line, and they are probably related with the outflow. As in many other water maser sources, the IRAS 4 water masers seem to trace selectively either the disk or the outflow. Considering the outflow lifetimes, the disk-outflow dichotomy is probably unrelated with the evolutionary stage of protostars. A possible explanation may be that both the outflow-maser and the disk-maser are rare phenomena and that detecting both kinds of maser around a single protostar may be even rarer.