PCI Race Radios Challenger II Foam Ear Pieces The Challenger II, built for racing communications, allowing the pit crew to relay vital data to the driver. Constructed to fit snugly under any racing helmet, it does not add unnecessary weight or bulkiness. Durably built for prolonged use, this is ideal for the toughest race tracks and intense driving situations. Features: The transducers are optimized for communications bandwidth allowing crystal clear transmission. Replaceable, comfortable foam rubber Complete with heavy duty cord and switchcraft mono plug