From the Manufacturer Mayfair - For Your Sense of Style. The Mayfair brand includes a wide variety of toilet seats that make lives easier. By paying attention to every detail, we deliver high quality products that will last for years to come. Innovative features and benefits are incorporated into our seats to help meet your customers’ needs and our wide variety of designs can be easily integrated into any bathroom style. Mayfair is over 50 years old and has become a recognized brand in the home. Mayfair toilet seats are designed to fit all manufacturer's round or elongated standard toilet bowls. Measuring for the correct size prior to purchasing your seat is very important. Using a tape measure, first measure the distance between the hinge post holes at the back of the lid area. The standard distance between the hinge post holes is 5-1/2-Inch. Once you have determined that the hinge post hole distance is standard, next you'll need to determine if your bowl is round or elongated. To do this, measure from the front center of the bowl to the area directly between the hinge post holes. The dimension for a round toilet is about 16-1/2-Inch. For an elongated toilet, the dimension is about 18-1/2-Inch.