
Kohler GP1078441
Score: 85/100
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 Kohler GP1078441 is a genuine OEM replacement flapper designed specifically for Kohler two-piece toilets featuring Class Five flushing technology. Its key strength is the precise 3.25-inch rubber seal that effectively prevents phantom flushes and maintains high-efficiency performance. However, it is incompatible with non-Kohler models and may degrade faster in hard water environments.
| Attribute | ![]() | ![]() |
|---|---|---|
3.25 inchesbest | 2 inches | |
1 countbest | 1 countbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Material & Durability(1) | ||
Seal Type | Rubber | Sealing Ball |
Design & Features(4) | ||
Chain Material | Standard | Stainless Steel |
Chain Adjustability | false | true |
Installation Type | Direct Replacement | DIY |
Flapper Type | Standard Flapper | Adjustable Flapper |
Packaging & Support(1) | ||
Warranty Period | 1 Year Limited | 5 Years |
Compatibility & Fit(6) | ||
Flush Valve Compatibility | Kohler Class Five | 2-inch |
Universal Fit | false | true |
Flapper Diameter (inches) | 3.25 inches | 2 inches |
Toilet Type Compatibility | Two-Piece | Standard |
GPF Compatibility | 1.28 | 1.28-5 |
Flush Valve Size | 3.25 inch | 2 |


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

Plumbing experts and editors from sites like Ferguson and CPE Supply highly recommend this part as the definitive OEM replacement for Class Five systems. They highlight its precise 3.25-inch seal as critical for preventing phantom flushes and its durable rubber construction for resisting corrosion.
Everyday consumers generally report high satisfaction, with many noting that the flapper perfectly fits their Kohler models and restores the toilet to like-new flushing performance. Common praise includes the ease of installation and the elimination of running toilet noises.

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.
“Perfect fit for my Kohler Cimarron-flush like new!”

“No more running toilet; lasted 2 years in hard water”

“Installed in 2 minutes, chain included.”



Choose Kohler GP1078441 for reliability; choose Korky 100BP for cost-effective generic fixes.