Scale: Unknown. A model of three pairs of launching wedges which are held in place on a rectangular baseboard by a block secured using three wooden bolts (one missing). The block is inclined at an angle of 20 degrees and is intended to show that at this inclination the wedges would spontaneously free themselves. The wedges have all been made in metal. The bolts, block, wedges and baseboard have all been painted in a uniform dark varnish. Two paper labels marked "14" and "4A" have been applied to the upper and under surfaces of the baseboard respectively. The baseboard is supported on two decoratively shaped brackets.