The Scan Helmet Mounted Ear Defenders clip into most standard helmet slots. With a noise-cancelling ratio of 30 dB, they are effective in reducing noise levels, whilst still allowing the wearer to hear normal conversation. The soft and wide PVC ear cushions enhance comfort, and the swivelling cup design allows for easy manoeuvring. The fluorescent yellow colour enhances visibility. These ear defenders have a Single Number Rating (SNR) of 30, meaning they will reduce noise by 30 decibels (dB). Conform to EN 352-32002 standard.