Duplex Unit for OKI C801,C810,C821,C830,C8600,C8800 Printers. This Duplex Unit effectively doubles the page capacity of the C8600, by printing on both sides of the paper. Enables the printing of A4 and A5 booklets and saves paper. User installable: slots straight into the back of the printer easily and without fuss. Prints paper weights: from 64gsm to 105gsm.