Helmet Shells?

One of our opponents this season was talking with our student manager about their helmets and how they have something like 8 different helmets but they use something that was described to me as "clip on shells that go on the outside of the helmet. They dont have 8 actual helmets, but they have shells that make it look like they do".

I've tried googling it but havent been able to find anything, curious if anyone knows the name or the company.

Thanks