In order to add PoE to an 891 router, the datasheet says you need “800-IL-PM-4 with 125W PSU.”  I had to use the Cisco Commerce Workspace to generate a config starting with the 800-IL-PM-4= part number and then added the 125W power supply there.  The following is what was shipped:

The 800-IL-PM-4= part is a daughter-card that is installed onto the motherboard of the 891 router.

WP_20150714_003

The 125W power supply had the Cisco part number of PWR-125W-AC.  The power supply is a LiteOn unit, model PA-2121-1-LF or 341-0502-01 (both were listed) putting out 12V, 3.5A of DC power on one rail and 53.5V, 1.55A on the other.

WP_20150714_005

Lastly, there were three baggies with hardware.

50-1807-02-A0 - 2 standoffs with two notches
50-1700-01-A0 - standoff with one notch
48-0421-01-A0 - 3 screws