^^^ This, but you will quickly find out that not every manufacturer makes a fit kit.Every batting helmet manufacturer makes a fit kit for their helmets. They can range from $3-$13 in price. Amazon carries many of them. Just make sure to buy the same manufacturer as the helmet to make it easier on yourself to install them.
8 years? Haha that is almost the original post is.^^^ This, but you will quickly find out that not every manufacturer makes a fit kit.
However, the fit kits are only foam padding with velcro so you can cut and design it to fit. This is what we have done for 8 years. FWIW, some are marketed as stain and microbe resistant.