The Bosch Heavy Duty Battery product line, made up of T6 with AGM (adsorbent glass mat) technology, T5 dual purpose and T4 batteries, was developed to withstand the extreme conditions that are unique to heavy duty vehicles, including extended idling and severe temperatures. The absorbent glass mat technology of the T6 battery incorporates special microfiber glass mats that absorb battery acid to protect the battery plates. The T5 and T4 batteries feature faster re-charging capabilities compared to conventional batteries, flushed tops for minimized risk of acid leakage, maintenance-free operation and an 18-month free replacement warranty.