The Blank Flange model no. EV01003 is available in the KF size 25 having dimensions 40,26.2,5 respectively and is offered in 304 stainless steel material.This product is the combination of two Flanges, a Center-Ring and an aluminum Clamp. Clamps are assembled with wing nuts to make it user friendly without tools. A constant application of pressure on the clamp insures a vacuum seal. The mating flange surfaces compress the O-Ring, which is held in place by a metal centering ring, to generate the vacuum seal.