The 7-Inch LEVEL5 flat box is used to apply a base coat of mud compound over taped drywall joints. Many finishers pair a 7” flat box with a 10” or 12” box to first fill the joint and then cover the seams after applying tape. If you’re new to automatic taping tools, the 7” flat box is an excellent foundation for your taping tool arsenal due to its great price and ease of use.