| 摘要 |
A signalling panel comprises two superposed transparent plies of plastic material peripherally secured together. The plates have a cylindro-convex configuration and the two plies are slightly spaced from each other to provide a slot therebetween for receiving a flexible sheet displaying a visible information through the two plies. The panel when narrow is secured to a rigid base while when wide is contemplated to be secured to a flexible base member. |
