Groco BB-Series Backing Block
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Groco BB-Series Backing Block
Seacock Sold Separately

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Groco BB-Series Backing Block

  • Select Seacock Size
  • 1/2" Thick for a Secure Installation, Will Not Swell or Absorb Moisture
  • Item #: 
    Model #: 
    Multiple Models Available
    Our Price:
    From: $44.99  To: $64.99
    44.99 64.99
    Please enter quantity below.

    Seacock Model
    Seacock Size
    Model #
    Shipping Weight
    750 and 1000
    3/4 Inch and 1 Inch
      0.05 Lbs.
      *In Stock!*
    Our Price: $44.99
    1250 and 1500
    1-1/4 Inch and 1-1/2 Inch
      0.50 Lbs.
      *In Stock!*
    Our Price: $54.99
    2000 and 2500
    2 Inch and 2-1/2 Inch
      0.05 Lbs.
      *In Stock!*
    Our Price: $59.99
    3 Inch
      1.00 Lbs.
      *In Stock!*
    Our Price: $64.99
    Click the "More Info" button above for specific information about that product.


    • Flanged seacock installation is improved with the use of a backing block between the valve flange and the hull
    • Each size fits multiple seacock sizes
    • Press threaded inserts into the hull side of the backing block into the holes that match the seacock flange
    • 1/2" thickness is rigid enough for a secure installation but flexible enough to conform to minor hull curvature
    • Will not swell or absorb moisture
    WARNING: This product MAY expose you to chemicals, which are known to the State of California to cause cancer, birth defects and/or other reproductive harm. For more information go to

    Groco TH-Series Bronze Mushroom Head Thru-Hull Fitting
    Item #: 502918
  • Select Thread Size
  • Material: Bronze, Retaining Nut is Not Included, Rated Above / Below Waterline
  • Marine UL listed
    From: $15.99
    To: $294.99
    Groco FBV Series Full-Flow Flanged Ball Type Seacock
    Item #: 503591
  • Select Bottom and Top Threads
  • Material: Bronze
  • Field Reversible Handle
    From: $48.99
    To: $384.99
    Model #:
    Multiple Sizes Available
    Groco BV Series Full Flow Ball-Type Seacock
    Item #: 503592
  • Select Bottom and Top Threads
  • Material: Bronze
  • Tri-Flange Base, Mounting Holes Match most Common Brands
    From: $149.99
    To: $2134.99
    Model #:
    Multiple Sizes Available

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