The Duet is a 1-Click-Switch Battery Plus Manual Sharpener. What a value! This 2-in-1 sharpener allows for precision battery powered sharpening. With on 1 click of the switch, the top quality blade becomes a standard hand-held manual sharpener. Great for office and classroom environments where quiet is intermittently important. Perfectly sized for travel or the on the go professional. Takes 2 AAA batteries (not included). Easy to clean, durable and compact. Use on graphite or colored pencils!