Review on Protect Your Child'S Hearing With Noise Cancelling Earmuffs - Perfect For Autistic Kids - 20DB NNR - Toddlers And Kids Age 3-16 Years by Floe Rankin

These are well-made, sturdy and fold up into a smaller size to pop in your bag. They fit my 6 year old well, covering his ears comfortably - the head piece is adjustable so I reckon they would work up to age 10 or so. They don't completely block out sound (which is fine, just letting you know what to expect), but they remove high-decible noise like trains, loud music etc. My son wore these when we went to a London show, he could still hear and enjoy it but it wasn't overwhelming for him. Well-priced, nicely packaged, highly recommended.