This is a 55mm GDome Extension Port for the GDome XL.
This product will come complete with seals for the front and back of the extension as well as a flat acrylic lens element.
Includes:
1 x Top Seal
1 x Bottom Seal
1 x Extension Port
1 x Flat Acrylic Lens Element
6 x Stainless Steel Screws (for the lens element)