Meet the Danco 5/8 in. D x 15/32 in. D #21 Rubber O-Ring (20 pack) — a precise, reliable seal designed to restore drip-free performance in a variety of plumbing connections. This rubber O-ring-friendly kit keeps your fixtures watertight, helping you avoid messy leaks and wasted water.
Key specifications
- Interior Diameter: 15/32 in
- Exterior Diameter: 5/8 in
- Wall Thickness: 0.047 in
- Material: Rubber
- Shape: Round
- Product Type: O-Ring
- Size designation: #21
- Quantity: 20 per package
- Packaging Type: Polybag
- Brand Compatibility: Fits American Standard, Aqua Seal, Cole
- Brand Name: Danco
Why this O-ring matters
O-rings are the frontline defense against leaks in many fixtures and fittings. The #21 size (5/8" outer diameter, 15/32" inner diameter) is a common fit for countless connections, and the 0.047" wall thickness provides a dependable seal under typical water pressure. With a 20-pack, you’ll have ready-to-use replacements on hand for quick repairs, preventing downtime and repeated trips to the hardware store.
Ideal for
- DIY homeowners performing routine faucet, valve, or connection maintenance
- Plumbers stocking spare parts for standard-use fixtures
- Emergency kits for leak prevention and immediate resealing tasks
Use cases and scenarios
- Replacing worn seals in common household fixtures that require a #21 O-ring to restore a tight seal
- Sealing supply lines and small valve connections where a 5/8" outer diameter is specified
- Having a ready supply of universal-size O-rings to tackle unexpected leaks during maintenance
Installation tips
- Ensure the mating surfaces are clean and free of debris before installation for an effective seal
- Lubricate the O-ring lightly with a compatible lubricant to ease seating and extend life
- Replace the O-ring if it shows signs of cracking, nicking, or hardening to prevent future leaks
Value you can trust
From Danco’s dependable lineup, this 20-pack of #21 rubber O-rings delivers consistency in size and material. It’s designed to fit widely used fixtures from American Standard, Aqua Seal, and Cole, making it a practical choice for ongoing maintenance and peak-season repairs alike. Keep a stock on hand and tackle leaks quickly without guessing the right size.
