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Research-based buying guide: We use the linked manufacturer or technical documentation. We have not independently tested this product.
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The earlier Exmate two-pack recommendation treated voltage and a long tool list as sufficient evidence of compatibility. That is not enough, particularly when a replacement changes battery chemistry.
Identify the original battery first
DeWalt’s service catalog identifies DW9057 as a 7.2V NiCd battery and lists a DW920K-2 application. That is evidence for the original DeWalt part; it does not approve a third-party NiMH pack or validate every tool number copied into a marketplace listing.
Voltage, chemistry and charger are separate checks
Match the tool’s documented battery requirement, physical interface and polarity, as well as the charger’s explicitly supported battery type. A pack fitting into the tool does not establish a suitable charging combination. Do not assume an older charger accepts NiMH because it previously charged a NiCd pack of the same nominal voltage.
Capacity is not independently measured runtime
A stated 3.5Ah capacity is not our measured capacity or a guarantee of a fixed runtime increase. Pack age, cell quality, storage, charging and workload affect results. Check identifiable manufacturer documentation, charger approval, supplier support and return arrangements before choosing a replacement.
Recommendation status
The specific Exmate pack’s tool list, charger compatibility, capacity and safety documentation remain unverified. Its product-specific endorsement is withdrawn. We have not charge-cycled the pack or compared endurance, and the earlier placeholder prices and unsupported extended-life claims have been removed.
Sources and documentation
Research checked November 8, 2026. Confirm the exact model, seller package and current instructions before purchase.
This post may contain affiliate links which means I may receive a commission for purchases made through links. Learn more on my Private Policy page.
