Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to cut duct board [title] Start with a full-sized sheet of duct board. [step] Standard duct board comes in sheets that are typically 48 inches (120 cm) wide by 96 inches (240 cm) long. On one side of the sheet is a thick layer of fiberglass insulation.

Ending1: The insulation is stretched and glued on in ways that make it easy to cut strips. Use a local fiberglass shop or contact a painter to print out some kits for you in the same color. Ending2: On the other is a thin foil backing which serves as the outside of the duct. [substeps] Duct board is manufactured in three different thicknesses : 1 inch (2.5 cm), 1.5 inches (3.8 cm), and 2 inches (5.1 cm). Ending3: This layer of insulation insulates the board from extreme cold. [title] Add 1 foot of insulation to the top row of sheets. Ending4: This insulation adds moisture to the air, allowing the board to expand further. [substeps] You can cut the top sheet or bottom sheet off with a flathead screwdriver.

Answer format: ending1/ending2/ending3/ending4