The series was developed to withstand the toughest of conditions. They contain a 5.4 mm diameter pre-polarized condenser element with a vertical diaphragm. This unique, Double Vent Protection System makes the mics greatly resistant to humidity and sweat. These mics are also designed with a Kevlar-reinforced cable relief, which is built to withstand the constant twists, bends and pulls that are part of the everyday use in harsh environments.