A:AnswerYes, they have different size ear cushions for different ear sizes. Usually THREE different sizes. Just monitor the volume setting. The child should not start losing his/her hearing until after 50, not pre-teen.
A:AnswerThe guide book in the packaging said it was water resistant but not waterproof. Essentially sweat and rain resistant, but not waterproof for anything too extreme.
A:AnswerThe earbuds are definitely OSHA approved. The earbuds can be used together as intended or you can use just one earbud by itself and it will work.