NEW - Includes FREE Flat Box Repair Kit - 3 blades & 2 pairs of box shoes AVAILABLE IN 8″, 10″, 12″ Inside Track High Capacity Finishing Boxes are built to help you conquer hard to finish areas. With fixed axel wheels set inside the width of the box profile letting the blade leave a clean finish, great for finishing beads and butt joints. High Capacity Drywall Master Inside Track Flat Boxes