Concorde's Sun Xtender Batteries are the original "AGM" (Absorbent Glass Mat) technology adopted by the U.S. military and worldwide airframe manufacturers since 1987. We offer their batteries to you for your mobile, grid-tied, and off grid renewable energy system. Sun X-Tender batteries are environmentally friendly and 100% recyclable. Call a solar expert today with questions or for assistance at 866-274-0642