bought to replace hinge on existing soft-close seat. fairly easy to install (if you have needle-nose pliers). stopped working within 24 hours.  read other reviews advising that hinges tend to pop out so I attempted to fix, but one hinge would not pop back into place and the toilet cover would not fasten back securely.  within 2 days, the back hinge of the toilet seat was cracked and now I've had to order a completely new toilet seat.  seems like a fairly straightforward fix, but Kohler needs to improve its execution and quality.