Easily clips onto helmets and fits most helmets. Euro slot system for easy attachment to compatible helmets. Sound Insulation: Designed with two layers of professional noise-absorbing foam and high-sealing solid cups, the earmuffs have excellent sound insulation, so you won't be bothered by noise. Function: An easy way to improve sleep quality, reduce noise damage to hearing, avoid noise interference, and effectively improve work and study efficiency. Material: ABS + Nylon + SS + Sponge NRR: 23dB SNR: 28dB Not applicable Class 5 SLC (80): 29.5dB Item Size: 21 * 15cm / 8.27 * 5.91 inches Item Weight: 307g / 10.83oz Package Weight: 315g / 11.11oz Due to being an imported product, there may be some scratches or dirt due to the manufacturing process or during transportation. Please understand this beforehand. "Please be sure to check the condition of the product in the images posted, and only purchase if you are satisfied."