Brother HL-7050N - Manual (Page 129)

4 - 2 OPTIONS
HL7050_US_UG_FM5.5
Small pad for lower tray unit and
stabilizer (SB-4000)
When you have the following printer options, you must install the
small pads or the optional stabilizer.
1 Lower tray 2 Lower trays 3 Lower trays
Non-mailbox unit
--------------------
Mailbox unit
(5 bins)
--------------------
Mailbox unit
(10 bins)
--------------------