The PETL Lights have been field tested by AFSOC personnel to a temperature of -20 degrees for an hour with no issues reported. The PETL Light enclosure is made of silicon so they perform in very low and very high temperature settings. One fireman personally reported having used the PETL Lights in close to 500 degree scenarios and it was still working. This gentleman brought the PETL Lights down to -109 degrees, then thawed the PETL Lights and they still continued to function. He also proceeded to drop them in boiling water and they still kept on functioning.