Consisting of  heavy cast iron tripod base with supporting rod also having rectangular plate of  dimension 15×10×1.5cm. The plate has two holes on three of its faces with tapping to carry the torsion heads enabling suspension with different configurations. The plate is suspended by means two strings of equal lengths from a rigid T Shaped clamp support provided with split chucks. Supplied with two torsion heads for suspension from a rigid vertical support.

This  bifilar suspension is used to measure the moment of inertia of a body about an axis passing  through its centre of gravity