Danger - Construction Area Keep Out! OSHA Contractor Preferred Max Sign warns readers that the designated area is an authorized only construction zone, and visitors must report to the site office. Contractor Preferred Max Signs have large dimensions 48"H x 96"W x 3/8"D constructed from corrugated plastic. These large signs are optimized for distant visibility to ensure people's safety. Mouting options include a wall mount, fence mount, or mounted on plywood. For shipping conveniences, signs are tri-folded and scored.