What is this?Microwave Waveguide Cover are accessory for the microwave oven and rice cooker,home,Kitchen ,etc.What will I get?Size:11.5cm x 6.5cm(4.52 inch x 2.55 inch);Material:Mica ;Color:Grey;In the package of:4 x Microwave Waveguide CoverIs there any advantages of the product?It is made of mica material,easy to install,High temperature tolerance, can withstand high temperature and steam, without deformation; Easy to clean; Prevent corrosion.How to use it?Steps of using:1. Check whether the installation position and model match that of a microwave oven. 2. Clean the inside of the microwave oven; 3. Place the Microwave Waveguide Cover in the appropriate position inside the microwave oven and make sure it fits perfectly into the microwave tube.