Fluidmaster K-400H-039 PerforMAX Toilet Fill Valve and 2" Flapper Repair Kit, Plastic, 1-Pack, Height 13.9in

This kit is a lifesaver if you have a noisy or slow-filling toilet. It combines the Fluidmaster PerforMAX Fill Valve and 2" Flapper Kit, which is basically their "high-performance" line. The big win here is the adjustable water-saving dial, which lets you control how much water goes into the bowl with every flush. It's also built to be universal, meaning it should fit most standard 2-inch flush valve toilets. The installation is pretty straightforward, and many people find that it fixes common "phantom flushing" or leaking issues instantly. ​There are a few things to keep in mind for the install. On the plus side, the height is adjustable, so it fits well in both taller and shorter tanks. The flapper is also made of a chlorine-resistant material, which is great if you use those drop-in tank cleaner tablets that usually eat through rubber. However, some users have noted that the water-saving dial can be a bit finicky to tune just right at first. Also, while it's marketed as quiet, it might still have a noticeable "hiss" depending on your home's water pressure. Overall, it's a solid, heavy-duty upgrade over the basic valves you'd find in a standard hardware store.

I have had this type of valve for many years which makes the installation of the working parts very simple. I just turned off the supply valve at the wall,drained the tank. Released the clamp on the old valve,slid it up and off and slid the new valve down on the stem, locked it in place with the ring and adjusted it to match the old one. Always replace the rubber flapper as it snaps in place and finish the job. I keep the stem and seal in case it might need to be replaced but so far it has been years since I put the first one in.