
Fluidmaster PerforMAX Flapper
Score: 88/100
Kohler GP1078440
Score: 80/100Rankings

The Fluidmaster 502P21 PerforMAX is a universal, adjustable 2-inch toilet flapper designed to resolve weak flushes, running toilets, and water waste in toilets with 1.28, 1.6, or 3.5+ GPF ratings. It features a dial-adjustable mechanism for customizing flush volume, Microban antimicrobial protection, and a solid frame to prevent twisting during operation. It is best suited for homeowners with most 2-inch flush valve toilets experiencing weak flushes, running toilets, double flushes, or high water use.

The Kohler GP1078440 is a genuine 2-inch shark-fin style toilet flapper designed as a replacement part for select Kohler one-piece toilets. It features a corrosion-resistant rubber construction with a red finish and includes an adjustable chain for secure sealing and efficient flushing. This part is specifically engineered for bottom outlet flush valves to ensure a reliable fit.
| Attribute | ![]() | ![]() |
|---|---|---|
2 inchesbest | 2 inchesbest | |
1 countbest | 1 countbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Material & Durability(4) | ||
Material | Rubber/Plastic | Rubber |
Seal Type | Solid Frame | Shark-fin |
Hard Water Resistance | true | null |
Water Resistance | true | null |
Design & Features(3) | ||
Chain Material | Standard | Not specified |
Installation Type | DIY | Direct replacement |
Flapper Type | Adjustable Flapper | Shark-fin |
Packaging & Support(2) | ||
Warranty Period | 5 Years | null |
Certifications | NSF/ANSI 61 | null |
Compatibility & Fit(4) | ||
Flush Valve Compatibility | Universal | Bottom outlet |
Universal Fit | true | false |
Toilet Type Compatibility | Standard | One-piece |
GPF Compatibility | 1.28-3.5+ | null |

Products in the top-left offer the best value (high score, low price).

Professional reviewers, including Home Improvement Expert Bob Vila, rate the Fluidmaster 502P21 as the best overall 2-inch flapper for addressing running toilets. It is praised for its ability to fix weak flushes, double flushes, and water waste. Manufacturer sources describe it as the 'gold standard' and 'high performance standard' due to its durability, adjustability, and Microban protection.
Search results do not provide direct consumer quotes or aggregated star ratings. However, implied praise from product pages suggests users value the reliable sealing, water savings, and ease of use for fixing running toilets. No recurring complaints are detailed in the available data.

