This Sony Walkman Portable is an ideal on-the-go companion. ESP SteadySound Electronic Shock Protection surpasses Sony's previous 20-sec. Buffer Memory system, and uses DSP (Digital Signal Processor) technology to provide longer continuous playback in more active uses.Complete Car Accessories permit versatile in-vehicle use of Discman player with no need to obtain additional components. Digital Mega Bass Sound System uses digital processing technology to produce rich, deep bass tones with extremely low harmonic distortion. Digital Volume Function provides very precise adjustment of volume level using a push button located on the front of the unit, while the volume level appears on the LCD display. 5 Playback Modes provide many choices in the playback of CDs: hear one track over and over, or hear tracks in Shuffle (random) order. Long Battery Life with 2 "AA" Batteries (up to 15 hours with ESP off) is made possible by advanced Sony design that allows extended battery life. High Image Metallic Finish Design With Heat Resistant Lid has attractive yet functional styling, and helps protect against high temperature build-up especially when using the Discman player in hot climates in a car. 2 Position Automatic Volume Limiter System (AVLS) maintains volume output at levels below distortion threshold for cleaner sound reproduction.