7075 aluminum and stainless less
Diameter of center hole: fits .22 to .45
The true diameter of the hole is in millimeters rather than inches.
For example 13mm and 33/64" = 13.096875mm
The actual 13mm hole is slightly smaller than 33/64" in diameter
Included in this kit:
1 x aluminum top fixture
4 x stainless lessBottom Cap