--- product_id: 592084472 title: "Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack)" brand: "captain o-ring" price: "14323CFA" currency: XOF in_stock: true reviews_count: 8 category: "Captain O Ring" url: https://www.desertcart.sn/products/592084472-captain-o-ring-replacement-seal-oring-for-sunsun-hw304a-hw304b store_origin: SN region: Senegal --- # Durable synthetic rubber Exact OEM spec fit Proudly USA assembled Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) **Brand:** captain o-ring **Price:** 14323CFA **Availability:** ✅ In Stock ## Summary > 🔧 Seal the deal with confidence—never let a leak slow your flow! ## Quick Answers - **What is this?** Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) by captain o-ring - **How much does it cost?** 14323CFA with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.sn](https://www.desertcart.sn/products/592084472-captain-o-ring-replacement-seal-oring-for-sunsun-hw304a-hw304b) ## Best For - captain o-ring enthusiasts ## Why This Product - Trusted captain o-ring brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Made in the USA:** Assembled by Captain O-Ring LLC with quality and warranty you can trust. - • **Precision OEM Fit:** Engineered to match SunSun HW304A/B and compatible models perfectly, ensuring leak-proof performance. - • **Dual-Pack Convenience:** Two premium o-rings included—replace now and keep a spare for future peace of mind. - • **Long-Lasting Durability:** Crafted from synthetic rubber designed to resist cracking and wear, extending your filter’s lifespan. - • **Universal Compatibility:** Fits a broad range of SunSun canister filters plus select Polar Aurora models—one solution for multiple filters. ## Overview This 2-pack replacement o-ring set from Captain O-Ring LLC offers an exact OEM-spec fit for SunSun HW304A, HW304B, and other compatible canister filters. Made from durable synthetic rubber and proudly assembled in the USA, these seals prevent leaks and extend filter life. Ideal for proactive maintenance or emergency fixes, they come in a convenient dual pack to keep your aquarium running flawlessly. ## Description Fix your leaking canister filter and have a spare on hand to prevent costly leaks with Captain O-Ring’s 2-pack replacement o-rings for SunSun canister filters. This o-ring is compatible with the following canister filter models: 304A (HW304A, HW-304A), 304B (HW304B, HW-304B), 404A (HW404A, HW-404A), 404B (HW404B, HW-404B), 602 (HW602, HW-602), 602B (HW602B, HW-602B), 603 (HW603, HW-603), 603B (HW603B, HW-603B) canister filters. Confirm your model matches one of the models above before purchasing to ensure you order the correct size that fits your filter. These o-rings are an exact match in size, tolerance, and material to the ones that came with your canister filter when it was new. Molded from OEM spec synthetic rubber for long lasting performance and durability. Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA! Review: Works for Polar Aurora 4-Stage External Canister Filter 525GPH! - I am so glad I was able to use these for my Polar Aurora 4-Stage External Canister Filter 525GPH. The company has discontinued Polar Aurora Canister Filters so they no longer make replacement parts for them. (Frusting when a company discontinued their product just after the warranty expires). What you can find is what is left over. An aquatics company told me that the SunSun is the same Canister Filter so it's replacement parts will fit. This o-ring fit perfectly and now my Canister is fixed. It wouldn't seal after I cleaned it. Water was dripping out from the side latch. Adding lubricant made it worse. I found out that you need to apply a small amount of a food grade lubricant on the o-ring everytime you open and close it to prevent the o-ring from cracking. I bought more incase of a future need. Review: Worked well! Fits and no leaks - Okay, so I'm am not 100% that the O-ring was the issue, but I had the filter for 7?ish years, and then the filter was dissembled for a couple months were it was just sitting open to air. I bought this new set, and installed it with some petroleum jelly. I do think that my leak was from the UV light cover not being fully inserted and locked in the filter head, BUT I am still glad I replaced the O-ring for my piece of mind. The price is very reasonable and you get two of them. If you even suspect that it is the o-ring, or your filter has been running for years without a change, go ahead and buy these. It can't hurt and now you also have a spare. Or just buy them now so if you do have a leak they are on hand. I keep my filter in one of those big bucket tubs that they sell for keeping toys and sports equipment in. I also have a water sensor that screams if it gets wet. I set the senor in the bottom of the tub, and the box with the battery to the side. It has definitely saved me when some leak occurs and the thing goes off at 5 in the morning screaming, with the tub catching everything and saving my floors. ## Features - Replacement Lid/Cover/Head Seal O-Ring for SunSun HW304A (HW-304A) and HW304B (HW-304B) canister filters, as well as the full list of compatible filters below. - Compatible with SunSun (Sun Microsystems) 304A (HW304A), 304B (HW304B), 404A (HW404A), 404B (HW404B), 602 (HW602), 602B (HW602B), 603 (HW603), 603B (HW603B) canister filters. - Approximate O-Ring Dimensions: 9.70” Inside Diameter (just under 9-3/4”), 10.14” (just over 10-1/8”), 0.21” Thick (between 3/16” and 1/4”). - Package includes two (2) o-rings (also called gaskets, seal rings, or rubber rings). Replace your old, worn, leaking o-ring and have a spare on hand for the future with this handy 2-pack. - Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA! ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0CP6C1FFD | | Best Sellers Rank | #63,828 in Pet Supplies ( See Top 100 in Pet Supplies ) #879 in Aquarium Filter Accessories | | Brand | Captain O-Ring | | Brand Name | Captain O-Ring | | Color | Black (Rubber) | | Customer Reviews | 4.0 out of 5 stars 65 Reviews | | Item Diameter | 9.7 Inches | | Manufacturer | Captain O-Ring LLC | | Material | Rubber | | Material Type | Rubber | | Model | SS-HW304A-OR-2pk | | Nominal Inside Diameter | 9.7 Inches | | Nominal Outside Diameter | 10.14 Inches | | Number of Pieces | 2 | | Part Number | SS-HW304A-OR-2pk | | UPC | 810061941538 | | Unit Count | 2.0 Count | ## Product Details - **Brand:** Captain O-Ring - **Color:** Black (Rubber) - **Item Diameter:** 9.7 Inches - **Material:** Rubber - **Nominal Inside Diameter:** 9.7 Inches ## Images ![Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) - Image 1](https://m.media-amazon.com/images/I/517fxzoXb4L.jpg) ![Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) - Image 2](https://m.media-amazon.com/images/I/61oNiUKyOfL.jpg) ![Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) - Image 3](https://m.media-amazon.com/images/I/71tnGR-ObUL.jpg) ![Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) - Image 4](https://m.media-amazon.com/images/I/715fa7-SyzL.jpg) ![Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) - Image 5](https://m.media-amazon.com/images/I/61xtrDC97qL.jpg) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Works for Polar Aurora 4-Stage External Canister Filter 525GPH! *by R***. on January 26, 2026* I am so glad I was able to use these for my Polar Aurora 4-Stage External Canister Filter 525GPH. The company has discontinued Polar Aurora Canister Filters so they no longer make replacement parts for them. (Frusting when a company discontinued their product just after the warranty expires). What you can find is what is left over. An aquatics company told me that the SunSun is the same Canister Filter so it's replacement parts will fit. This o-ring fit perfectly and now my Canister is fixed. It wouldn't seal after I cleaned it. Water was dripping out from the side latch. Adding lubricant made it worse. I found out that you need to apply a small amount of a food grade lubricant on the o-ring everytime you open and close it to prevent the o-ring from cracking. I bought more incase of a future need. ### ⭐⭐⭐⭐⭐ Worked well! Fits and no leaks *by K***R on November 22, 2024* Okay, so I'm am not 100% that the O-ring was the issue, but I had the filter for 7?ish years, and then the filter was dissembled for a couple months were it was just sitting open to air. I bought this new set, and installed it with some petroleum jelly. I do think that my leak was from the UV light cover not being fully inserted and locked in the filter head, BUT I am still glad I replaced the O-ring for my piece of mind. The price is very reasonable and you get two of them. If you even suspect that it is the o-ring, or your filter has been running for years without a change, go ahead and buy these. It can't hurt and now you also have a spare. Or just buy them now so if you do have a leak they are on hand. I keep my filter in one of those big bucket tubs that they sell for keeping toys and sports equipment in. I also have a water sensor that screams if it gets wet. I set the senor in the bottom of the tub, and the box with the battery to the side. It has definitely saved me when some leak occurs and the thing goes off at 5 in the morning screaming, with the tub catching everything and saving my floors. ### ⭐⭐⭐⭐ Pretty standard replacement ring. *by K***A on May 7, 2026* Haven't replaced yet but I bought before so I will update once I replace this weekend ## Frequently Bought Together - Captain O-Ring – Replacement Seal Oring for SunSun HW304A, HW304B Canister Filter (2 Pack) - Marine Color 9w Lamp Bulb, Spare Bulb for Sunsun Hw-303b 304b 404b Jup-01 Filter Cf400, Cf500, G23 2 Pin, - Replacement Impeller for SUNSUN Aquarium Canister Filter (HW304A/HW304B) --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.sn/products/592084472-captain-o-ring-replacement-seal-oring-for-sunsun-hw304a-hw304b](https://www.desertcart.sn/products/592084472-captain-o-ring-replacement-seal-oring-for-sunsun-hw304a-hw304b) --- *Product available on Desertcart Senegal* *Store origin: SN* *Last updated: 2026-06-02*