OKI B721N OKI Digital Mono Printers. Enhanced performance, ease of use and security features make the B721n perfect for productivity-minded companies.These printers can also help control your impact on the environment ENERGY STAR compliance - With their lower power consumption, these printers meet the government's standards for energy efficiency.Duplex (2-sided) printing - This technology allows for savings in energy and resources, in addition to using less media.One-piece consumables - Long-lasting, user-replaceable printer cartridges remain friendly to your budget while lowering the number of items to dispose of or store.