Note: For Stainless Steel K Cups Only, Not For Aluminum K Cups Material: 7075 aluminum and stainless less Diameter of center hole: fits .22 to .45 Note: 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