Clips on to your books so you can read in the dark. Read in really poor light on your own e-reader device using the really tiny book light & e-reader adapter. How does it work? Push the adapter onto the top of your e-reader & slide the book light clip through the hole.• Rotates to a 90 degree angle position• Press switch marked light to operate LED light• Book light is fitted with 3 x AG (LR41) batteries• Before use open battery compartment at back & remove insulation tape• To open the battery compartment slide cover downwards