
Kohler GP1078441
Score: 85/100
American Standard 3-Inch Flapper
Score: 70/100Rankings

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.

The American Standard 738920-0070A is a genuine OEM replacement toilet flapper assembly designed specifically for American Standard Cadet 3 model toilets. It offers a reliable, pre-assembled solution for standard 1.6 GPF flushing needs. However, its plastic construction and strict model compatibility limit its versatility and long-term durability compared to premium materials.
| Attribute | ![]() | ![]() |
|---|---|---|
3.25 inchesbest | 3 inches | |
1 countbest | 1 countbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Material & Durability(2) | ||
Material | Rubber | Plastic |
Seal Type | Rubber | Standard |
Compatibility & Fit(4) | ||
Flush Valve Compatibility | Kohler Class Five | American Standard Cadet 3 |
Flapper Diameter (inches) | 3.25 inches | 3 inches |
GPF Compatibility | 1.28 | 1.6 |
Flush Valve Size | 3.25 inch | 3 inch |

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.
“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.”



