The Rock Fall Alaska Freezer safety boots are a cold temperature boot, developed with specialist materials that are certified for use in temperatures as low as -40 Degrees C. Includes a 3M Thinsulate B600 Ultra Fursulate fur lining and a shock absorbing solid nitrile rubber outsole. Lace up fastening with metal alloy eyelets. Meets Standard EN ISO 20345:2011 S3 CI HRO SRC ASTM F 2413-18 M/I/C PR.