Assorted Large Drilled Ball set, set of 12, A 3mm hole is drilled through the center of each ball. Every set comes in a convenient plastic storage case, with a foam bottom that holds each ball firmly in place
Doppler Effect Demonstration Apparatus, 92dB buzzer, 0.8m tether. Nylon cord is 2ft 8in attached to a rugged ABs handle 8.5in long, (1in diameter), swing the apparatus and students will be able to hear the change in frequency, Dimensions: 4.5 x 5 x 3 in