For some U.S. drivers, this year’s hottest car accessory is a chunk of black plastic.

Ford and Rivian gave one to each of their EV owners free. General Motors is selling one for more than $200. And drivers of other brands will have to wait until they, too, can obtain an adapter — and unlock access to the promised land of Tesla EV chargers.

Much like the “videotape format wars” Betamax and VHS fought in the 1970s and ’80s, in the new millennium automakers have vied for dominance over ways to charge EVs. Tesla created a proprietary, compact plug design; most other automakers used a shared design for a larger plug.