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Forespar 905104 MF850 Marelon PTFE Ball Valve 1/2 Inch

Manufacturer

Forespar

<h3>About Forespar Products Corporation</h3><p><strong>Forespar Products Corporation</strong> has been a cornerstone of the marine industry since its founding in 1966. The company's origin story is as practical as the products it makes: <a href="/7351-forespar">Forespar</a> was started by lifelong boater Robert Foresman simply because he wanted a telescoping whisker pole — and couldn't find one good enough. That hands-on, solve-a-real-problem philosophy has guided every product decision in the decades since, growing Forespar from a single-product idea into a large and diversified supplier of sailing and boating products serving the world market.</p><p>Headquartered in Rancho Santa Margarita, California, Forespar operates a state-of-the-art manufacturing facility that handles the entire product lifecycle in-house. The team uses CAD/CAM design, a full machine shop, plastic injection molding, and carbon composite processing — capabilities that allow Forespar to maintain the tight tolerances and consistent quality that demanding sailors and powerboaters expect. This vertical integration is a key reason the brand has earned such a loyal following across the globe.</p><h3>Marelon&reg;: The Forespar Innovation That Changed Marine Plumbing</h3><p>One of Forespar's most celebrated contributions to boating is <strong>Marelon&reg;</strong>, a proprietary polymer composite formulation engineered specifically for marine plumbing applications. Marelon fittings — including seacocks, thru-hulls, and vented loops — deliver exceptional resistance to corrosion and electrolysis, two of the most persistent threats to below-waterline hardware. Because Marelon components weigh roughly half as much as traditional bronze equivalents, they help reduce overall boat weight without compromising structural integrity. The precision-molded plumbing systems built with Marelon are UL approved and meet A.B.Y.C. standards, giving boaters confidence that their below-deck plumbing is as safe as it is durable.</p><p>Forespar vented loops and thru-hull fittings are trusted by both sailors and powerboat owners who need reliable, maintenance-friendly solutions that hold up in the harshest saltwater environments. The corrosion-free nature of Marelon also means fewer inspections, less maintenance, and longer service life compared to metal alternatives.</p><h3>Sailing Performance Gear: Poles, Vangs, Furling &amp; More</h3><p>Beyond plumbing, Forespar is equally renowned for its performance sailing hardware. The brand's lineup of <strong>spinnaker poles and whisker poles</strong> — available in aluminum, carbon fiber, and composite materials — is designed to help sailors extract maximum downwind performance. The locking telescoping designs allow for quick adjustments on the water, and the carbon fiber options in particular combine a featherlight feel with impressive structural strength. For racers and cruisers alike, Forespar poles represent a genuine upgrade in sail handling capability.</p><p>The <strong>Leisure Furl</strong> in-boom mainsail furling system is another flagship product line bearing the Forespar name — a sophisticated solution for sailors who want easy, reliable sail stowage without sacrificing performance. Rounding out the sailing hardware catalog are boom vangs, sail handling hardware, davit systems, and safety equipment, making Forespar a one-stop source for outfitting a sailboat from deck to transom.</p><h3>Powerboat &amp; Cruising Accessories</h3><p>Forespar's reach extends well beyond racing sailboats. The brand's <strong>davit systems</strong> and the innovative <strong>Nova Lift</strong> make deploying and retrieving dinghies, tenders, and outboard motors significantly easier for cruising families and liveaboards. Forespar's marine lighting products offer dependable illumination for navigation and on-deck use. The Flopper Stopper — a uniquely Forespar solution — helps reduce uncomfortable rolling at anchor, a quality-of-life upgrade that any offshore cruiser will appreciate.</p><p>Whether you're racing offshore, cruising coastal waters, or maintaining a powerboat at the dock, Forespar has built products specifically for your challenges. The brand's commitment to innovation, quality manufacturing, and real-world boating experience has made it one of the most trusted names on the water for more than five decades.</p>

Part Number

905104
06/01/2036 1:47 AM
Sale Price

$140.40

In Stock (10+)

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Usually delivered within 2 days

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No Hassle Returns

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Live-in-stock inventory

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Fitment guaranteed

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Product Details

The Forespar 905104 MF850 is a precision-molded marine ball valve constructed from high-strength glass-reinforced Marelon composite material. This half-inch through-hull valve is engineered specifically for marine applications where corrosion resistance and reliability are critical.

Key Features:

  • Glass-reinforced Marelon construction for superior strength and durability
  • PTFE (Teflon) ball and seals provide smooth operation and long service life
  • Completely immune to corrosion, electrolysis, and galvanic degradation
  • Lightweight design reduces installation stress on through-hulls and fittings
  • Suitable for above and below waterline applications
  • Controls inlet and outlet water flow for marine sanitation, cooling, and livewell systems
  • Full port design maintains maximum flow capacity

Marelon ball valves offer significant advantages over traditional bronze valves in marine environments. The non-metallic construction eliminates the risk of dezincification and electrolysis that can compromise metal valves over time. The smooth PTFE ball provides reliable sealing and effortless quarter-turn operation even after extended service. Ideal for seacocks, engine cooling systems, washdown pumps, and any marine plumbing application requiring dependable shut-off capability.

Products specifications

Mount Type

MF850 1-1/2

Port Type

5" L x 3-1/2" dia.

Thread Size

1-1/2"

Good

Easy to navigate.

Lowest prices I found on the net and great customer service! Fast shipping too!

Awesome and quick ship time. Very informative with the ship date<br> Will be doing business with them again

Great prices and quick shipping.

Easy to navigate, fast shipping and able to get parts that are practically discontinued. Great experience.

OK. Hope to receive my order by the specified date.

Good product, great price, will do business again.

Ordering is quick and easy and product was just as described

Very fast shipping and order processing!! Extremely competitive pricing; after wading through the internet and finding 'good' pricing (from sketchy vendors) these guys are tops!

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