Corner Trim - Inside CornerInside Corner Trim INSIDE CORNER TRIM IS USED WHEN TWO METAL PANELS INTERSECT AT THE INSIDE CORNER OF A WALL. INSIDE CORNER TRIM CREATES A FINISHED LOOK AND PREVENTS WATER PENETRATION. IT'S TYPICALLY THE LAST PIECE OF METAL FLASHING THAT'S INSTALLED ON A METAL SIDING INSTALLATION. IF YOU ARE UNSURE ABOUT TRIM PLACEMENT, A TRIM PLACEMENT GUIDE CAN BE VIEWED HERE: IF YOU ARE ORDERING MULTIPLE QUANTITIES, YOU MAY CHANGE THE QUANTITY IN YOUR CART BEFORE