Helper Design: with on-board fuel gauge, integrated LED battery charge level indicator allows user to monitor battery using. Built-in integrated microchip prevents overcharging and self-discharge. professional lithium battery for Ridgid 18V lithium battery R840087, R840083, R840085, R840086, AC840089, AC840085, AC840086, AC840087P Series. Works Fine: fit RIDGID 18V Lithium system of cordless drill tools, works with Ridgid 18-Volt lithium battery charger R86092. Fade-free Power: over 500 cycle times, high capacity 4.0Ah lithium battery 18V, long lasting/ more run-time and powerful in working Replacement Ridgid 18V Battery Model: for RIDGID 18V Lithium-ion Battery Pack R840083, R840085, R840086, R840087, R840089, AC840085, AC840086, AC840087P, AC840089 Series Compatible with Ridgid 18V Tools Model: for RIDGID 18V Lithium-ion cordless drill tools Compatible with Ridgid 18V Lithium Battery Charger: R840091, R840093, R840095, R86092, R840086, AC840094