Korky 100BP
Score: 90/100Fluidmaster Adjust-A-Flush Flapper
Score: 92/100Rankings
The Fluidmaster 502P21 is a high-performance adjustable 2-inch flapper designed to resolve running toilets and weak flushes with precision. Its main trade-off is the need for initial dial adjustment to find the optimal setting, which may frustrate users seeking a simple drop-in fix. It is best suited for homeowners with post-1994 toilets who want to conserve water and improve flush efficiency.
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.
| Attribute | | Fluidmaster Adjust-A-Flush Flapper |
|---|---|---|
2 inchesbest | 2 inchesbest | |
1 count | 2 countbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | | Fluidmaster Adjust-A-Flush Flapper |
|---|---|---|
Material & Durability(2) | ||
Material | Rubber | Plastic |
Seal Type | Sealing Ball | Solid Frame |
Design & Features(3) | ||
Chain Material | Stainless Steel | Metal |
Installation Type | DIY | No-tool |
Flapper Type | Adjustable Flapper | Adjustable |
Packaging & Support(3) | ||
Pack Quantity (count) | 1 count | 2 count |
Warranty Period | 5 Years | 5 years |
Certifications | NSF/ANSI 61 | |
Compatibility & Fit(4) | ||
Flush Valve Compatibility | 2-inch | 2 inches |
Toilet Type Compatibility | Standard | Post-1994 |
GPF Compatibility | 1.28-5 | 1.28-3.5+ GPF |
Flush Valve Size | 2 | 2 inches |
Products in the top-left offer the best value (high score, low price).
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.
Professional reviewers, including Bob Vila, rate the Fluidmaster 502P21 as the best overall 2-inch flapper for addressing running toilets and weak flushes.
Everyday users commonly praise the product for its ability to quickly fix running toilets and weak flushes while offering significant water savings through dial adjustment.
“lasted 7 years in hard well water”
“5 minutes, no tools”
“saves hundreds of gallons yearly”
