68Appendix A: Safety, Environmental, and Regulatory InformationRTC Battery SafetyWARNING: Using an incompatible batterymay increase the risk of fire or explosion.Replace the battery only with a compatiblebattery purchased from Dell that isdesigned to work with your Dell computer.Do not use a battery from other computerswith your computer.Audio SafetyWARNING: Excessive sound pressurefrom earphones or headphones can causehearing damage or loss. Adjustment of thevolume control as well as the equalizer tosettings other than the center position mayincrease the earphones or headphonesoutput voltage, and therefore the soundpressure level.The use of factors influencing the earphones orheadphones output other than those specifiedby the manufacturer (e.g. operating system,equalizer software, firmware, driver, etc.) mayincrease the earphones or headphones outputvoltage and therefore the sound pressure level.The use of earphones or headphones other thanthose specified by the manufacturer may lead toheightened sound pressure level.Ergonomic InstructionsWARNING: Improper or prolongedkeyboard use may result in injury.WARNING: Viewing a display or externalmonitor screen for extended periods oftime may result in eye strain.For additional information concerningergonomics, please go to the RegulatoryCompliance homepage on www.dell.com atthe following location:www.dell.com/regulatory_compliance.