Why do teams wear different helmets? College Football?

I have noticed that a team, (ex: Alabama, Florida,Kentucky) will come out wearing different helmets.
Some players wear a helmet with a smooth top helmet and a circular pattern of round holes at the top, while other players on the same team wear a helmet with a ridge running front to back and oval holes along the sides of the ridge.
Why don’t they all have the same one?

There are various manufacturers of Helmets on the market now, which previously weren’t available. The different helmet mfr’s have different designs. It’s up to the personal preference of the player. If I were the athletic director of a college program I wouldn’t allow some of the more stylized versions like the Schutt ION 4D or ION-T-EGOP-II, which look too bizarre, but then I’m from the old school. The worst helmet is the one that has a little kick out in the back. (Riddell Revo)They look strange on teams with traditional uniforms like Alabama, Notre Dame, and Penn State.

Some of these new designs claim better concussion protection.

SEC Coaches Signing Football Helmet

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