Typically, the term adapter describes a product designed to join two components that don’t naturally align, and battery adapters are no exception. Battery adapters are helpful for situations where you start a project only to discover your cordless DeWalt drill has a depleted DeWalt battery. Rather than halt your progress entirely while you wait hours to recharge, an adapter allows you to use a fully charged Milwaukee battery instead, for example. In theory, as long as you have at least one brand of battery charged and the required adapters, you can mix and match across different manufacturers.

In order for the adapter to work, however, it must conform to specific plastic shapes that align the contact points to accommodate one type of battery and another brand of tool. These battery packs slide and click into place, so the fit must be exact for consistent power transfer. These adapters typically range in price from $12 to $25 and are often made by third-party manufacturers. Tool-makers do not typically endorse or support adapters unless they’re specifically made by the company.