These are Apple's own battery cases so they're also compatible with accessories with Lightning connectors.
Brad's Deals Editor Michael,
This Apple iPhone 7 Smart Battery Case drops from $99.99 to $69.99 at TechRabbit. Plus the shipping is free. This is the lowest price we could find for one of these cases by $12. These cases have a soft-touch silicone shell that protects against drops and scratches and the built-in battery can add around 22 hours of usage to your iPhone. Sales tax is charged in most states.