Fluidmaster Inc 501P21 Red Toilet Flapper 21 Pack

Product Description

The FLUIDMASTER INC 501P21 is a red toilet flapper engineered for reliable performance in harsh water conditions. Built from thermoplastic material and incorporating built-in Microban antimicrobial protection, this flapper resists breakdown caused by bacteria — a common failure point in chemically treated or high-mineral water supplies. It ships as a bulk pack of 21 units, making it a practical stock item for plumbing contractors, service technicians, and facilities maintenance teams who need consistent, readily available replacement parts. The 501P21 carries a 5-year warranty and is designed as a direct replacement for the flapper portion of the 555C assembly.

This flapper is suited for residential and light commercial toilet repair applications where water chemistry is aggressive or where standard rubber flappers degrade prematurely. The thermoplastic construction and Microban treatment make it a go-to choice in installations served by well water, heavily chlorinated municipal supplies, or water with elevated bacterial content. The 21-unit pack format supports van stock for plumbers running high-volume service routes or managing multi-unit properties.

Key Features

• Thermoplastic construction resists chemical degradation in harsh water conditions
• Built-in Microban antimicrobial protection helps prevent flapper breakdown caused by bacteria
• Direct replacement for the flapper portion of the 555C assembly
• Bulk pack of 21 units supports contractor van stock and multi-unit service jobs
• 5-year warranty coverage

Compatibility

Designed as a direct replacement for the flapper portion of the Fluidmaster 555C assembly. Verify seat diameter and tank configuration before installation on other toilet models.

Installation Notes

Toilet flapper replacement is a standard plumbing service task performed by licensed plumbers or qualified DIYers. Before servicing, shut off the water supply at the angle stop valve below the tank and flush to empty the tank. Inspect the flush valve seat for wear or mineral buildup before installing the new flapper, as a damaged seat will cause continued leakage regardless of flapper condition. Follow all applicable local plumbing codes when performing toilet repairs.

Technical Specifications

• Material: Thermoplastic
• Antimicrobial Treatment: Built-in Microban
• Package Quantity: 21 units
• Unit of Measure: EA
• Package Weight: 3.75 pounds
• Warranty: 5 years

Standard Information

• Brand: FLUIDMASTER INC
• Manufacturer Part Number: 501P21