Fluidmaster 500 Flapper
Score: 75/100
Korky 100BP
Score: 90/100Rankings

The Korky 100BP Ultra High Performance Flapper is a universal 2-inch toilet flapper designed to maximize flush performance while conserving water across various gallon-per-flush ratings. Constructed from exclusive chlorine-resistant red rubber, it offers superior durability in harsh water conditions and features adjustable settings for precise water optimization. It is best suited for homeowners with standard 2-inch toilets in areas with chlorinated, hard, or well water.
The Fluidmaster 500 is a universal 2-inch solid frame flapper designed for older 3.5+ GPF toilets, featuring Microban technology for durability. Its main limitation is the lack of adjustability and limited consumer feedback for long-term reliability. It is best suited for homeowners with standard 2-inch valves on older toilets needing a reliable, no-frills replacement.
| Attribute | Fluidmaster 500 Flapper | ![]() |
|---|---|---|
2 inchesbest | 2 inchesbest | |
1 countbest | 1 countbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | Fluidmaster 500 Flapper | ![]() |
|---|---|---|
Material & Durability(5) | ||
Material | Vinyl | Rubber |
Seal Type | Solid Frame | Sealing Ball |
Chlorine Resistance | Unknown | true |
Hard Water Resistance | Unknown | true |
Water Resistance | Unknown | true |
Design & Features(4) | ||
Chain Material | Metal | Stainless Steel |
Chain Adjustability | false | true |
Installation Type | Standard | DIY |
Flapper Type | Solid Frame | Adjustable Flapper |
Packaging & Support(2) | ||
Warranty Period | 1 year | 5 Years |
Certifications | Unknown | |
Compatibility & Fit(4) | ||
Flush Valve Compatibility | 2 inches | 2-inch |
Toilet Type Compatibility | Pre-1994 (3.5+ GPF) | Standard |
GPF Compatibility | 3.5+ GPF | 1.28-5 |
Flush Valve Size | 2 inches | 2 |

Products in the top-left offer the best value (high score, low price).
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Professional reviewers and plumbing experts, including those from Clorox, highly endorse the Korky 100BP as the longest-lasting flapper available. Editors at supply sites praise its high performance and precise water control, noting that it significantly outperforms generic brands in chlorine resistance tests. The product is highlighted for its universal design, making it ideal for contractors who need a single solution for various toilet brands, with no performance drop across different flush volumes.
Everyday consumers rave about the product's longevity, with many reporting it lasted up to seven years in harsh water conditions. Users frequently praise the ease of installation, noting it takes only five minutes without tools. Common themes include strong flush performance despite water savings and perfect fits for brands like Kohler. Recurring complaints focus on the chain being too long and occasional initial seal issues that require adjustment.
“lasted 7 years in hard well water”

“5 minutes, no tools”

“saves hundreds of gallons yearly”

