The 3M Attest system provides results within 24 hours. 3M Attest 1261 biological indicators for 270°F/132°C gravity steam cycles. Self-contained BI for 270°F/132°C gravity steam cycles consists of a Geobacillus stearothermophilus spore strip, sealed glass ampule with growth medium and a bromocresol purple pH indicator dye system, blue color coded cap with holes for sterilant penetration and a filter as a bacterial barrier, and a chemical indicator on the label that changes from rose to brown when processed. After sterilization, the vial is “crushed” to join the growth media with the processed spore strip. The BI is incubated for 24 hours for a visual color change readout. A color change to yellow indicates surviving spores and a positive result. Store at USP controlled room temperature. Latex-free. Sold 100 per box.