3M PELTOR Optime II Earmuffs, 30 dB, Helmet Mounted Ear Defenders H520P3E-410-GQ - see photos for attachment version supplied in this listing - other attachment versions are listed separately 

P3E ear muff defenderattachment for use with MSA safety helmets.

• Reduces noise levels by up to 30 decibels (SNR).
• Sealing rings filled with a combination of liquid and foam.
• Large space inside the cups helps minimise heat and moisture build-up.
• Soft, wide, foam cushions help to reduce pressure around the ears.
• EN352-3:2002 tested & certified.