Do these covers work with bucket seats and bench seats?

Universal fit means they're built to work with most standard front seating. Bucket seats and bench seats can both use them—just test-fit before you commit to the install, especially if your seat has unusual contours or aftermarket modifications.

Will these slide around while I'm driving, or do they stay in place?

Construction and grip details aren't specified—your mileage depends on the material and how well they anchor to your seat frame. Secure them snug during install and check them after your first few drives to make sure they haven't shifted.

What's the return window if they don't fit my seats?

Contact ModSupply directly for their current return policy on seat covers. Most retailers allow returns within 30 days if the covers are unused and in original condition, but confirm the exact terms before you buy.