Backing Block


  • Each size fits multiple seacock sizes. 
  • Press threaded brass inserts into the hull side of the backing block into the holes that match the seacock flange. 
  • Rigid 1/2" thickness provides secure installation but is flexible enough to conform to minor hull curvature. 
  • Will not swell or absorb moisture.
  • Made from an environmentally friendly PVC foam specially formulated for marine applications.

Additional Information
Fits Seacock Sizes 750 AND 1000
Diameter 4.29
Insert Threads 5/16"-18