Warning Overhead Works Sign for construction site safety management. Our signs ensure that you have the appropriate control measures in place to identify potential hazards and mitigate against them. Signs are available in a wide range of sizes and materials and are suitable for long term outdoor use. Most popular sizes are 16″ x 12″, 24″ x 16″ and 32″ x 24″. Don’t see the sign or size you are looking for? You can call us on 025-31212 or email firstname.lastname@example.org to discuss your requirements. Discounts available on Bulk Orders.