Product dimension (L*W*H CM): φ25.5
Inner packs dimension (L*W*H CM): 38.5*26.5*9.5

It is used for physics teaching demonstration and student experiment in group at middle schools, colleges & universities and vocational schools. It is used with electronic stopwatch and counter to study quantitatively vibration period is not connected with amplitude when the simple pendulum vibration declination is less than 5 degrees, that is isochronous; to study simple pendulum vibration period T is not connected with quality of pendulum ball; to study simple pendulum motion period is proportional to square root of pendulum length; to study simple pendulum vibration period is inversely proportional to square root of acceleration of gravity and to determine acceleration of gravity value.