Indian Spherometer Double Disc All Brass Steel Legs for Physics Laboratory. This Spherometer comprises a circular metal table 50 mm in diameter with three accurately positioned painted steel legs and ordinary steel screw thread working in long adjustable brass bearings. A circular scale is carried on the thread and a scale on the table, enabling the user to take accurate micrometer-type readings. It is mostly used in physics laboratories in Bangladeshi schools & colleges. Labtex is the supplier and wholesaler of Single Disc and Double Disc Spherometers.