TENWIN BATTERY ERASER WITH DIFFERENTELECTRIC ERASER INSTALL BATTERY 1 Rotate battery cover in the direction of arrow on the end of product. tall two No according the positive and negative marks As the picture shows Press and rotate back the lid Operation Press the button and the rubber starts to rotate Rotate back and forth to erase all place you needn't + Replace rubber Back to the original, can use it again Pull out the rubber clip after the rubber was frayed if need to use diameter