ICL cells are completely fused without the use of low melting intermediate glasses or cements. In other words, quartz is fused to quartz and glass is fused to glass. This eliminates strains due to differences in coefficients of expansion found in cells fused with intermediate low melting glasses. Because of the fused construction, the window joints are unaffected by all types of cleaning solutions. 'G' = Optical Glass Guaranteed Transmittance: at 320 mu about 75% Permissible Deviation inmore Matching: at 320 mu max. 1% If cells are cleaned carefully after use, their transmission characteristics will remain fairly constant. Improper use or poor cleaning will result in staining or etching of surfaces thus reducing transmission and increasing light scattering. Cells bought in pairs are matched in pathlength and material without extra charge less