Replacement 4000mAh 21.6V Battery for compatible cordless impact drivers and wrenches. Designed as a direct replacement for specified tool models and part numbers to restore runtime and maintain consistent performance on the job. Key benefits Restores runtime and productivity: 4000mAh capacity and 21.6V output provide the power needed to finish common drilling, fastening, and fastening removal tasks without frequent interruptions. Direct compatibility: Fits the listed models and part numbers for straightforward installation and proper electrical connection. Consistent performance: Stable voltage supports steady tool operation under typical load conditions. Practical replacement option: Ideal when the original battery is worn, holds little charge, or is no longer reliable. Compatibility Compatible with models SID 22A, SID 4A22, SID 8A22, SIW 22A, SIW 22TA, SIW 22TA 1/2, and SIW 6ATA22 Replacement part numbers 2018498, 2136393, 2136395, 2183185, 426176 Performance and function Capacity: 4000mAh Voltage: 21.6V Function: Replacement battery pack for cordless impact tools to restore usable runtime and maintain nominal voltage during operation Form factor: Designed to match the fit and electrical interface of the compatible tool models and part numbers listed above Why this replacement solves common problems Eliminates unpredictable run time caused by aged or failing batteries Avoids downtime from frequent battery changes by providing usable capacity for extended tasks Provides a compatible, plugin replacement that does not require tool modification Typical use scenarios Construction site fastening: a worn battery to keep impact drivers running through deck fastening, stud work, and framing tasks without frequent recharging. Maintenance and work: Use as an on hand replacement for service technicians who need consistent power for repetitive fastening and unfastening on equipment and machinery. Automotive and mechanical tasks: Restore full tool functionality for impact wrench tasks such as wheel nut removal and assembly on light vehicles and equipment. What to expect in use Simple swap in place of the original pack for the specified models and part numbers Immediate to nominal tool operation and typical runtime for a 4000mAh 21.6V pack No tool modification required when used with listed compatible models Notes Use only with compatible chargers and tools specified for 21.6V battery packs Refer to your tool documentation for safe handling and charging practices