The Ear Defender takes its job seriously to protect your ears from damage. 
It comes standard with a 30mm universal attachment which slides and clips into place in the integrated slot on the side rail of your SHK-1 helmet.
**This product is not compatible with the SHK-1 Full Brim (Vented or Non-Vented).
Meets ANSI S3.19-1974 noise reduction standards
Noise Reduction Rating (NRR) = 24 Decibels 
Easy to mount on the side of your SHK-1 helmet — so you can protect your head and ears at the same time 
Easily Adjustable — To comfortably fit over your ears 
Product Care: 
Wipe down with a clean, damp cloth