Works great simple to installFor years my Kohler toilet seats have been coming loose as a result of which I have been re-tightening the screws with a screwdriver ever week or two. I happened to notice elsewhere that some toilet seats come with more satisfactory screw arrangements and wondered why the Kohler seats did not. Imagine my delight when a search on Amazon led to these BornFeel screws, which were more affordable and less hassle than buying new toilet seats. It was not at all clear which size to buy. It may not matter. I ordered a 2-pack of the 4.6 mm thin screw. When they came they worked fine, although I did need to replace the large plastic washers which came with the screws with the large stainless steel washers from the existing Kohler arrangement. Now a month or so later the 2 toilet seats that I converted are still tight.I had just bought a new toilet seat and the included plastic bolts were crap. The seat came loose after a week. I knew there were metal ones out there but I had never seen this design before.Install wasn't super difficult. I removed the seat completely, took the screw out of the rubber piece, and then used a little finesse to twist and push them through the hole. The "ball" should be under the hole and the flared out end should rest on top of it. Once I got the seat lined up and put the metal bolt/washer in, it was as simple as screwing them in place. Didn't even have to hold the rubber underneath the seat. Just make sure you don't over tighten it.The seat is VERY secure. Wish I had known about these earlier.I had about given up finding something to secure a new toilet seat to my useless Toto toilet ( never buy one ). You can not get to the underside of the hole that the seat fastens to. The engineer that designed this probably died of frustration trying to use his toilet. I saw these on Amazon and a last ditch effort tried them. You have to really crank the screw tight but once they tighten it the seat will not move a bit. You have to carefully push the ball inside the rubber sleeve firmly but if you bought the right model it will go in the hole and hold the seat.You can't tighten the screws or they'll fall inside the toilet.These amazing little things did the trick! I'll admit they were a little bit of a challenge to get threaded through the hole but I was prepared for that from reading other reviews. Before using these I had to tighten the nasty plastic screws almost daily or risk sliding off the throne along with the seat. I can tell you i put them on around a month ago and have yet to have ANY movement of the seat! Buy them!! Buy them now it is absolutely worth it!!Will not fit Kohler single piece toilets too fatMy toilet seat has always had a habit of working itself loose over time. I found myself tightening the little plastic nuts two or three times a week. A few weeks ago, I installed a bidet under the toilet seat. The screws that attached the seat were a little short to properly accommodate the added thickness of the bidet. As a result, the seat move around a lot and my toilet sessions were like riding a cheap carnival ride.After doing a bit of research, I found these screws on Amazon. I ordered them and installed them. Since I replace the existing hardware with these, my gos have been much less precarious and I haven't had to tighten the screws. I ordered more sets for our other toilets.