STERIS Spordi® Biological Indicator Discs are specifically designed for determining the effectiveness of steam, ethylene oxide (EO), dry heat or hydrogen peroxide vapor sterilization. Each disc is made from special filter paper inoculated with both Bacillus atrophaeus (BA) and Geobacillius stearothermophilus (GS) bacterial spores. This minimizes inventory because one package of Spordi Biological Indicator Strips can be used to check the efficacy of steam, EO and dry heat sterilizers.