Datasheet: https://www.juniper.net/assets/us/en/local/pdf/datasheets/1000597-en.pdf
...
Slots: 4 ( 1/2 slots?) MIC Only
The router is environmentally hardened
Size: 3.5 rack units (U; that is, 6.125 in., or 15.55 cm) tall.
SDN-ready
https://www.oreilly.com/library/view/juniper-mx-series/9781491932711/ch01.html
Each MX104 router has three built-in MPCs (FPC 0 through FPC 2)
ring: bottom left: 0/0 , build-in 10G: 2/0/0,...
