These 16pcs set meets all your everyday needs. Small size are suitable for 25ml, 50ml, 100ml, 250ml, 500ml of beakers, while big size are for 250ml, 500ml, 1000ml, 2000ml, 3000ml of beakers . you can place inside a container of liquid or solution is seated on a magnetic stirrer, and a rotating magnet or multiple stationary electromagnets to create a rotating magnetic field Wide application: the stir plate magnet bar can work with various types of magnetic stirrers or heating stirrers, and is often applied to stir a liquid or solution in scientific research, universities and laboratories Quality material: the rod magnetic mixer is made of quality PTFE, and cylindrical shape and smooth surface will reduce friction and smooth , for laboratory color: White Material: PTFE Package Contents: 16 x PTFE magnetic stirring bar Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.