Epson ERC-39 Compatible POS Ribbons for :Epson MU310 Epson MU310S Epson MU311 Epson MU311S Epson MU312S Epson ERC39 Omniprint OPC-311 Size : 12.7mm X 4.2MThe price listed here is for one (1) unit of ribbon onlyThis product comes with Six (6) units in a box and is sold by the box only