Pack of 5 pcs. 20A Slow-Blow (Time Delay) Ceramic Fuse. If you add 20 to cart, that will be a box (100 pcs.) Rated Voltage: 250v, 250 volts (also replaces 125v) Question: Why does my microwave fuse often burnt after I replace fuse not long? Answer: Microwave fuse should use a slow-blow type because its loading will increase much when the microwave starts. It needs a little overload when the equipment starts(only a short time).