Additional features include an "on demand" blue backlit LCD display to show station tuning; a digital clock, whose functions include an alarm and 20-minute sleep timer that can be set to wake to an iPod as well as radio. The device features an auxiliary input and stereo headphone output positioned in the rear with rubber covers to protect them from the elements; a detachable matching secondary speaker for stereo sound; a built-in battery charger; and the ability to run on standard AA alkaline or NiMH/NiCad rechargeable batteries (or by an included AC adapter or 12V power source. The iSongBook, which measures approximately 6.25 x 11 x 2.25 inches for the clock/radio with the slave speaker, includes seven dock adapters for compatibility with the iPod mini, iPod photo, and other earlier generation iPod models, a 6 foot audio cable for proper room positioning with a rewind mechanism for cable management, and an optional carrying bag.