This 15646 Block Off Plate is installed in place of a PA Block on an E-47, 57, or 60 unit, which makes an E-47 unit an E-46 (an E-60 an E-50), which has no power angle. Also used during diagnostics to determine cause of problems. LONG OBSOLETE from Meyer, we have a small quantity to offer (10) first come first serve! Includes bolts and O Rings for installation.