Single speed. This centrifuge consists of a substantial cast-iron body enclosing a steel pinion and worm drive fitted with a ball-thrust race. It comes with a removable crank handle and one thumb screw clamp to clamp the machine to a table. The head has captive union rings to accommodate 15 ml buckets. The body is baked in a hammertone finish. Complete with plastic buckets and glass centrifuge tubes.