Package includes: 16 * PTFE magnetic stirring bar (8 * big size/1.38inx0.31in, 8 * small size/0.79inx0.27in). These 16pcs set meets all your everyday needs. Small size bars are suitable for 25ml, 50ml, 100ml, 250ml, 500ml of beakers, while big size bars are for 250ml, 500ml, 1000ml, 2000ml, 3000ml of beakers .