The 4-Bin Mailbox supports bin ’empty’ and ‘full’ sensing. Up to three units may be installed. Any combination of Offset Stacker and 4-Bin Mailbox for up to a total of 3 devices may be configured. This unit supports up to 100 sheets of paper (20 lb., 75 gsm) per bin of A4, A5, A6, JIS B5, Executive,Folio Letter, Legal, Oficio or Statement sizes. Only paper (16 to 24 lb, 60 to 90 gsm) may be used with this unit.