This sturdy plastic ring is formed to snap easily onto a plate. The clear plastic is easy to keep clean. Dishwasher safe up to 50°C (125°F). Guard is 30mm (11/4″) high. Large size fits plates 215 to 250mm (81/2 to 10″) external diameter. Small size fits plates 150 to 190mm (6 to 71/2″) external diameter.