This is American Standard , Very popular in the U.S. market. Please check your product fit or not first. Diameter of center hole are 22 caliber - 9/32 - 0.2813inch, 30 caliber - 3/8 - 0.375inch, 9mm - 27/64 - 0.3906inch. Please see the picture . Utilizing a hardened steel drill bushing this fixture will give you years of use. Included in this kit: (1) aluminum Top fixture (3) stainless steel Bottom Cap . Trap not included. Our Product are exquisitely crafted and do not have a center mark. Please see the picture..syi