NSAW NSAW R-6098 Reflection of Sound Apparatus

We 'NATIONAL SCIENTIFIC APPARATUS WORKS' are offering Reflection of sound apparatus. For proving that angles of incidence and reflection are equal for any setting. A protractor (actual D) is screen printed on a superior quality board. It consists of two independent arms containing 8" long steel pipes. When one arm is set at any arbitrary angle and other is adjusted until, one listen the maximum sound. At the position of maximum sound two angles will be equal as indicated by the D reading Apparatus consists of two light metal pipes with plastic funnels at their ends, other ends of pipes are mounted in such a way that the angle in between can be varied from 0-180 degree, provided with 0-180 degree scale on base plate.