Create round concrete bases for small structures, signs, light poles, and mailboxes. Made from specially formulated cardboard, these tubes are lightweight and easy to cut with a utility knife, yet strong enough to hold wet concrete without buckling and swelling, keeping your base's shape. They keep their strength in rain and wet soil for up to 24 hours, so your concrete has time to cure.

Apply a mold-release lubricant (not included) before pouring your concrete and then cut them away when the concrete has hardened, usually after 48 hours. Or leave them on and they'll break down in the ground over time. They're recyclable and comply with OSHA requirements for releasing only trace amounts of hazardous chemicals.

When these tubes will stick out more than 2 ft. above the ground, build frames or side braces to keep them upright and steady above ground.