PURE BEAM SLIDE FOCUS: Pack two powerful beams into one and seamlessly transitionwith no halos or hot spotsbetween short and long-range viewing. COASTs SLIDE FOCUS system enables you to seamlessly transition between spot and flood beam with the push or pull your finger. RECHARGEABLE-DUAL POWER: Each COAST Rechargeable-Dual Power product comes with a ported ZITHION-X rechargeable battery or a non-ported ZITHION rechargeable battery and is compatible with either COAST Extreme Performance alkaline batteries or other brand-name battery types, depending on the product. This provides you the cost savings of using rechargeable and the flexibility of reverting to alkaline.