This OKI Feeder is guaranteed to work with OKI ES9431, ES9541, PRO9431, PRO9541, PRO9542 printers.Print up to 500 DL envelopes in under 12 minutes.Envelope sizes supported through feeder:Envelope standard sizes: DL, C4, C5, C6, C7Custom sizes:Widths from 2.5″ – 13″ (64mm – 330mm)Lengths from 3.5″ – 15″ (89mm – 381mm)or2.5″ x 3.5″ (64mm x 89mm) to 13″ x 15″ (330mm x 382mm)Printer – supported media:Straight-through paper path supports envelopes, magnetic media, polyester, transparant film and heavier stock (up to 360gsm)3″ x 5″ (76mm x 127mm) cards to 52″ (1320mm) bannersSRA3 and A3+ 13″ x 19″ (330mm x 483mm)Improved window envelope support:Raised and angled envelope stack ensures smooth separation of typically challenging media