Cup measures 4" in diameter at the top. Saucer measures 5 7/8" in diameter. Shows minor signs of use but has never seen the inside of a dishwasher.
Fire-King Lusterware was made by Anchor Hocking Glass Co. from the late 1930's to the late 1970's. In the 50's and 60's it was sold in 5 and 10 pound bags of flour and laundry detergent. It was often also given away at gas stations as a promotional item if you purchase 8 or more gallons of gas.
The original designs were very unique and were not dishwasher safe but were made of slow expanding borosilicate glass that could go from the oven to the refrigerator without breaking.
This particular set would make a wonderful addition to your collection or to replace a damaged or missing piece of a set.