The waveguide covers the hole through which the microwaves are fed into the oven cavity from the waveguide

It acts as a barrier to stop grease and food particles from entering the opening of the waveguide

If the part begins to arc or spark during a cook cycle, it needs to be replaced. Continued use will cause burning of the paint and cavity and will eventually damage the magnetron tube.

This waveguide cover fits the following Sharp microwave models:R540DK, R540DW, R530EW, R530DW, R530EK, R530ES, R530DK, R520DW, R520JK, R520JKF, R520JW, R510HWF, R515EK, R519EW, R520D,R510HW, R510HWF, R515EK, R519EW, R510FK, R510FW, R510HK, R510HKF, R510DK, R510DW, R510EK, R510EW, R508FS, R508HS, R509FW, R510CW, R501CW, R501FK, R501FW, R508DK, R430EW, R440DK, R440DW, R501C, R430DK, R430DQ, R430DW, R430E, R428JK, R428JKF, R428JW, R428JWF, R426HS, R426HSF, R426HW, R426HWF, R425EW, R426HK, R426HKF

R426HQ, R415EW, R420DK, R420DW, R420EK, R410FK, R410FW, R410HK, R410HW, R410DK, R410DW, R410EK, R410EW, R408JWF, R409EW, R409HK, R409JS, R408EW, R408JK, R408JKF, R408JW, R403JK, R404FK, R405DK, R408D, R1520LQ, R1520LW, R402FW, R1512, R1514, R1514F, R1520LK, R1506, R1510, R1510F, R1511, R1502, R1505, R1505F, R1505LK, R1406F, R1500, R1501, R1501C, R1214F, R1405, R1405F, R1406, R1210F, R1211, R1211F, R1214, R510FW, R1200