Tape & Reel (TR) is the solid enclosure in which optical attenuator is packaged.The RF Attenuator comes in 0805 (2012 Metric) packaging, which makes it convenient to ship overseas.
E-TA2012 T 4DB N3 Features
E-TA2012 T 4DB N3 Applications
There are a lot of Nidec Copal Electronics E-TA2012 T 4DB N3 Attenuators applications.