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Model # 501P21

Internet # 100584018

2 in. Universal Longest Lasting Toilet Flapper with Microban

This item has been discontinued.
The Home Depot no longer carries this specific product.

$4.59 /each




Model # 501P21

Internet # 100584018

Only Fluidmaster has toilet flappers with built-in Microban protection. The Microban protection keeps the flapper cleaner by fighting flapper breakdown due to bacteria on the flapper itself. The 501 Universal Longest Lasting Toilet Flapper is best for use in 3.5 Gal. per flush toilets made before 1994. The 501 Universal Longest Lasting Toilet Flapper is Chlorine Resistant and has a solid frame for ultimate reliability. Flappers with a solid frame do not twist and provide the best seal. Replace or fix your toilet flapper with a Fluidmaster toilet flapper.

  • Built-in Microban fights flapper breakdown due to bacteria on the flapper itself
  • Chlorine and hard water resistant
  • Solid frame for ultimate reliability
  • Easy to install, works on most toilets
  • Extended 5-year warranty

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Chain Included 
Corrosion Resistant 
Plumbing Part Type 
Toilet Flapper 
Warranty / Certifications
Manufacturer Warranty 
5 year 


Rated 3.8 out of 5 by 15 reviewers.
Rated 5.0 out of 5.0 by Only for 1993 or older toilets For those people having problems with this flapper, be aware that models 500, 501, & 503 are only for use with old toilets manufactured in 1993 or earlier (3.5, 5.0, or 8.0 GPF). If you use this flapper in a 1994 or newer toilet, you will experience problems. It is not designed for the water-saving, low-flush toilets. For 1994 or newer toilets (1.6 GPF or less), you must use model numbers 502, 5051, or 5403. See the Fluidmaster website for more information. December 1, 2012
Rated 5.0 out of 5.0 by First time item I only bought a flange for the toilet. It works and does not leak. July 14, 2015
Rated 2.0 out of 5.0 by Flapper Sticks Also I had the same experience as kenfixerupper. The flapper seals nicely and fixes the slow leak, but it consistently sticks in the up position. If you don't "jiggle the handle" and make sure it closes, you waste a lot of water if you don't catch it right away. The design seems to have not taken into consideration the diameter of the standpipe. To solve the problem of sticking, I had to file down the arms creating more space between them so they don't stick to the standpipe. It works well now, but it took a lot of fussing with a file grinding it down until it stopped sticking. Definitely not a quick or simple fix for the beginner. February 13, 2011
Rated 5.0 out of 5.0 by great performance for American Standard toilet built in the 1960's I have worked with mechanical things most of my life. In my work, I have come across many different flapper designs. For an American Standard toilet made in the 1960's, this flapper cannot be beat. The toilet probably has a better flush with this flapper than it did when it was new. The location where the chain anchors to the flapper is perfect for this old toilet. The fancy clip that attaches to the toilet tank lever appears to be a very well thought out design. Even if I had to replace this flapper every year, I would not mind because this flapper makes this particular toilet work very well. It appears that we are probably using less water now with this flapper, but I don't own the equipment needed to prove this. Try this flapper on your old toilet. It might not be so sturdy, but it works very well. September 1, 2014
Rated 5.0 out of 5.0 by So easy!! I bought this to replace a Fliudmaster flapper that was installed well over five years ago. I didn't think it would be so easy. I took the old part with me just to make sure it was the same part. It was an exact fit! Took me all of five minutes to replace it. Very happy....and so's my wallet. No more running toilet and high water bills for me! September 27, 2014
Rated 2.0 out of 5.0 by good seal, Sticks UP I have replaced plenty of flappers. Never had a problem with Fluidmaster or these Dura Flush flapper valves until recently. The flapper stayed in the UP position. I had to keep adjusting the chain length to get it to flush normally. Occasionally it does hang up. However the seal is very good. I just have to keep an eye on it especially if we are on our way out for an extended period of time. December 6, 2011
Rated 1.0 out of 5.0 by Flapper Sticks Bought this flapper Nov 21. Installed it. Works.... OK fine. Another toilet began leaking around the flapper so went back to my favorite local Home Depot (I really do like the store and the people !) and thought, why not, pick the one that worked last time -- for an identical toilet tank. Nooooo... though this one definitely cured the slow leak around the edges (both tanks only 3 years old -- the seat was clean and smooth, no burrs). However... the one I bought three weeks ago sticks around the standpipe, it does not fall back down... it holds on. Water runs full force for hours if we don't hear it. Put washers on the standpipe "ears" to widen the stance... it still sticks. The normal water use of 3000 gal per month has climbed up to 9000 gal per month. Costing me $$$. March 23, 2010
Rated 2.0 out of 5.0 by Stay away I have been doing plumbing maintenance work for over 15 years. And these flappers have a week thin plastic eyelet where the chain attaches. It will break very soon if you live anyplace where there is hard water. Truly a design flaw. The company also does not stand behind their products. Do yourself a favor and stick with the Korky all rubber flappers. They outlast these by far, and unlike Fluidmaster they stand behind their product. December 5, 2013
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