The DataSafe DX 4DX-21B and the other 4DX models share the DX 2DX’s level of affordability, convenience, and reliability, but with four cells instead of two. This gives the 4DX maximum power with all of the convenience of the DataSafe DX series. With it’s calcium flat-plate battery construction, optimal grid and lug design, and heavy duty plate lug and strap, the DataSafe DX 4DX-21B is built to handle high-rate UPS applications. The four-cell construction makes the battery as efficient as possible. Maintenance and installation with the 4DX-21B is hassle-free. Each DataSafe DX battery has a patented Slide-Lock post seal. Both the included fire-resistant PVC cover and the optional larger fireproof container seal the battery to protect it from breaking and leaking during a fire.