There is a Tape & Reel (TR) solid enclosure around the optical attenuator.The RF Attenuator is convenient to ship overseas because it is packed in a 0805 (2012 Metric).
E-TA2012 T 4DB N4 Features
E-TA2012 T 4DB N4 Applications
There are a lot of Nidec Copal Electronics E-TA2012 T 4DB N4 Attenuators applications.