Lithium Polymer, or LiPO batteries, are high-discharge batteries designed to be used with upgraded or high-end airsoft guns to drastically increase performance. Because LiPO batteries can discharge at a much faster rate a noticable reduction from the time you pull the trigger to when a BB is actually fire (called trigger response) is observed. LiPO batteries also give the operator the choice to increase the voltage from the typical 9.6v NiMH batteries to an 11.1v LiPO battery and thus increasing rate of fire. While not all guns are capable of handling the power of a 11.1v LiPO battery, many are able to be upgraded by the Airsoft Station professional airsoft gunsmithing department to handle the stresses of using these batteries!
Additionally, LiPO batteries require a special LiPO balance charger to properly charge. Always store LiPO batteries in a safe and cool place and never charge them unattended.