Some toilets (fewer than 10% in North America) have concealed trapways (aka flat sides or skirted bowls), without access to the seat mounting hardware on the underside of the bowl. These toilets require Top Mount Toggles sold separately (click here). Bath Royale's Top Mount Toggles fit all industry standard toilets with 5/8 inch diameter toilet seat mounting holes.
Example of Toilet Requiring Top Mount Hardware: (click here)
Top Mount Toggle Installation Instructions: (click here)
IMPORTANT (KOHLER toilets): Kohler's Top Mount toilets have smaller 3/8 inch diameter mounting holes, which require Kohler's proprietary anchor nuts. If you are replacing an existing seat and the anchor nuts are in good condition (not loose or corroded), reuse them with the screws included with your Bath Royale toilet seat. If the anchor nuts are loose or corroded, you must replace them before installing a new seat. Kohler's top mount anchor kit and nuts can be purchased on Amazon (links below):
NOTE: Below are videos that may be helpful regarding Kohler’s anchor kit: