It consists of a wooden box fitted with a glass tube fitted in the centre of its top surface. The glass tube is open at the end attached to the wooden box, and the other end has a torsion head for sealing the tube. The cradle holding the permanent magnet is suspended using a thread through the glass tube and is attached to the cap of the glass tube. The wooden box has glass sliding doors, to prevent any outside disturbance from entering the box, and levelling screws to ensure that the base of the wooden box is perfectly flat. The base of the box has a mirror which is used to measure the deflection.