A giant slide rule. Made of 3 2x4s fastened together with wood and screws; center portion can be removed. U. S. Patent numbers 2,168,056, 2,170,144 2,285,722, 2,422,649, 2,500,460 and 2,534,695 are listed at the top, to the right, of the copyright date and company. 3 functions are listed in the top and bottom sections, and 4 functions in center section. Ruler marks are black. Most numbers are black, with some in top and center sections in red. Number of functions per section, ruler marks, and number colors are identical for the other side. Clear piece of platic with a black line down center is the slide - works for both sides. Metal hooks in topand bottom sections - hung from wall. Color: WH,BK,RD