Solid Bronze or DZR Inline Ball Valves, What’s the difference

Groco Inline valve
A common question is which material do I select for my thru hull and seacock fittings. Solid Bronze or DZR Bronze are the two different materials commonly used for seacocks in marine applications. Solid bronze has many advantages and in particular Groco have additional design features that enhance the inherent quality advantage of the solid bronze material even further:

Material Composition:

Solid bronze seacocks are made from a single material, just bronze. Bronze is an alloy of copper and tin, which is known for its strength, corrosion resistance, and durability and is the traditional choice for marine applications due to its favourable properties. ‘Bronze’ is more corrosion resistant than ‘DZR Bronze’ which is a type of brass alloy that contains additives to help prevent corrosion, solid bronze will maintain its corrosion resistance in saltwater environments for far longer as it is naturally corrosion-resistant due to the presence of copper and tin in the alloy.

Strength and Durability:

Solid Bronze Flanged Seacocks and Inline Ball Valves are known for their strength and durability. They have a proven track record in marine applications and are often chosen for their reliability and robustness due to the inherent strength of the material resulting in superior long-term durability when compared to DZR Bronze.


The adage of buy well and buy once really does apply to seacocks and inline ball valves. Solid bronze is slightly more expensive than DZR but you will get that marginal extra cost returned over years of faithful service, it’s really worth spending that little bit more upfront to avoid replacement and/or high service costs going forward.

Design Features:

Groco have added some key features as standard into their seacock and inline ball valve range to further lengthen their lifespan and improve ease of maintenance:

  • 1-1/4″ sizes and larger include grease zerk for lubrication and/or draining meaning you can easily grease the seacock or inline ball valve without needing to remove it.
  • A bonding attachment enables easy earthing of the valve, minimising electrolytic corrosion
  • Manufactured with either solid stainless steel balls or chrome plated solid brass balls that are not a hollow ball, improving longevity
  • Handles are manufactured from extremely durable stainless steel and are reversable enabling opening in either direction, this not only helps fit your seacock in a tight space but also allow you to exercise (open/close) it easily.


In summary Groco Solid Bronze seacocks, inline ball valves and skin fittings are amore durable and resistance to corrosion than their DZR counterparts.

Contact us at Marine-Products-Direct on +44 (0) 1202 600011 or and we will be happy to assist in your selection of marine hardware.

Groco Seacocks FBV Series

Solid Bronze Groco Flanged Seacock