Bulk is the solid enclosure in which optical attenuator is packaged.The RF Attenuator can be shipped overseas conveniently because it is packaged in 0805 (2012 Metric).
E-TA2012 1DB N5 Features
E-TA2012 1DB N5 Applications
There are a lot of Nidec Copal Electronics E-TA2012 1DB N5 Attenuators applications.