A gas porous media which comprises a material having a low coefficient of thermal expansion that is capable of retaining 99.99% or more of particles of a size of about 0.003 microns and larger at 0.2 slpm/cm2 while demonstrating a permeability of 3.5×10−12 m2 and a porosity of around 62% is disclosed. The porous media can be fabricated into a frame that is capable of retaining 99.9999999% of particles greater than 0.003 μm in diameter at 8.3 sccm/cm2 with a permeability of 3.0×10−13 m2 and a porosity of around 53%. The porous medias can be tailored by changing the raw materials and process to yield media with a range of porosities and that exhibit permeability between 1.0E−13 and 1.0E−11 m2. The porous media are used in frames for supporting a pellicle and a reticle in a parallel relationship to each other. The frames may comprise porous media in its entirety or the porous media can be fabricated and sealed into a solid support frame.