Buy replacement batteries at SpinLife. We offer free shipping and a 30-day return policy on all replacement batteries. And with brands like Interstate and MK Battery you're sure to find replacement batteries to fit your mobility needs. Choose from Interstate's Sealed Lead Acid (SLA) or MK Battery's Gel. The SLA batteries are completely maintenance free and the battery acid is completely sealed for safety and prevention of evaporation. Gel batteries feature a battery acid that is a gelatin-like semi-solid mass. They produce no fumes and generally have a longer lifespan than other types of batteries. Two of our top selling replacement batteries include Interstate's 12V 12AH Sealed Lead Acid and MK Battery's U-1 Sealed Gel Batteries and all of our batteries are sold in pairs.