Round pipe post is another low-cost sign post and extensively used in supporting street or traffic signs at any desired height and angle. 2 3/8" outside diameter suits for most mounting hardware. Sign panels are either bolted directly through the post or clamped to the outside of the post. Hot-dip galvanized finish resists rust and weathers corrosion. However, round sign post should be field-drilled or used special clamps to attach signs.