Attest steam biological indicator lets you monitor load control of sterilization and helps prevent infections.. The indicator features color-coding for fast referencing and ease of use.. 3M's Attest rapid readout biological indicator provides quick results, within 1 hour when incubated using 3M's Attest auto-reader 390.. It works with 270° F gravity steam sterilizers.. This indicator assures sterility by challenging extremely resistant Geobacillus stearothermophilus spores..