RESPIREX DIELECTRIC BOOTS 20kV Protection for Over Eight Hours. Class 2 (EN 50321-1:2018 AC). ● An electrically insulating dielectric boot with an integral steel toe cap and vulcanized rubber sole for superior slip resistance. The Respirex Dielectric boot provides protection of up to 20kV over the complete boot for over 8 hours, and 35kV over the sole for 3 minutes.