It has an electronic timer unit on which there are four 4 mm sockets, two for gates and another two for solenoid and a toggle switch for release and catch the ball. The other unit consists of heavy retort
stand. The said retort stand carries two base boards. Out of them, one is solenoid holding base of size 149x97x113 mm providing with two banana sockets of 4mm. When the toggle switch is on ‘Catch’
position, the current is flowing in solenoid and it produces magnetic field and a steel ball make a attraction towards it. Another base connected to retort stand is of steel base on which the ball is dropped having base of size 115x60x2 mm. As well as switch is positioned on release, their, breaking the contact between solenoid and ball is dropped on steel plate and there is some time displayed on the timer. Supplied with steel ball of 12 mm & 18 mm diameter.