Fold-up safety floor signs make your "caution" clear on all four sides. These patent-pending signs come with an innovative device called the Lockin' Arm" that lets you place them quickly and easily with a couple of quick flicks, locking the 25" high sign solidly into place to prevent collapsing. In addition signs are made of large, molded plastic panels that offer an easy-to-read message area. Virtually indestructible. 1 1/2" thickness allows for easy space saving storage.