From this menu:
Manual Envelope Size
Manual Envelope Type
You can:
Rough/Cotton
Custom Type <x> (where x represents
Identify the envelope size being manually loaded.
7 3/4 Envelope
9 Envelope
10 Envelope* (US)
B5 Envelope
C5 Envelope
DL Envelope*
Other Envelope
Identify the envelope type being manually loaded.
Envelope*
Rough Envelope
Custom Type <x> (where x represents