NEW YORK (AP) — Walmart will require customers to wear face coverings at all of its namesake and Sam’s Club stores, making it the largest retailer to introduce such a policy that has otherwise proven difficult to enforce without state and federal requirements.

The company said the policy will go into effect on Monday July 20, 2020 to allow time to inform customers. About 65% of its more than 5,000 stores and clubs are located in areas where there is already some form of government mandate on face coverings. Walmart joins a growing but still short list of retailers, including most recently Best Buy, to require masks at all of its stores.