Features: ajc replacement compatible with para systems mbk 520i ups battery exact oem replacement guaranteed to fit easily and precisely maintenance free agm technology, no need to add acid or water ever important: you must re-use: your existing cabling and hardware. These are replacement batteries only note: it is your responsibility to verify the batteries being ordered match the batteries in your unitprior to placing your order. We are not responsible for incorrect orders ul recognized component buy with confidence. Our backed by easy 30-day returns and 12-month warranty disclaimer: our products are not affiliated with or authorized by para systems