CSB HC1221W - (Replaces HC1217W) 12 Volt/5.1 Amp Hour (21 Watts) Sealed Lead Acid Battery with Recessed Polarized Terminals Innovative plate structure greatly increases energy/density ratios Increased current delivery for high rate discharge Reduced internal resistance for superior performance Uniform plate formation for consistent capacity No-spill design - Lead-calcium VRLA (AGM) technology