MIAMI GARDENS, Fla. – Guardian Caps are soft, protective helmet covers that the NFL will allow players to wear during games this season in an effort to reduce head injuries.

Several players have worn them through the first seven weeks, though Tua Tagovailoa, like most NFL players, said Monday he won’t wear the headgear when he returns from his latest concussion. Players have cited several reasons, including comfort and aesthetics, for not wearing them.

The NFL has mandated the use of caps during contact training for most players since 2022. Quarterbacks, kickers and punters are the only position groups that are not required to wear the caps during practices that involve contact.

There are six types of helmets that the league has approved that players can wear during contact practices that do not require the Guardian Caps.

Tagovailoa has been cleared by medical experts to return to play for the Miami Dolphins after suffering his latest concussion in a collision with Bills defenseman Damar Hamlin in Week 2.

If Tagovailoa clears the NFL’s concussion protocol after practicing Wednesday, he is expected to start Sunday against the Arizona Cardinals.

Here’s a look at the Guardian Caps and how they are used in the NFL:

What are Guardian Hats?

The 12-ounce padded shells attach to the top of a player’s helmet. The NFL has said research shows that when a player wears the protective gear, it results in a reduction in impact severity by at least 10%. That number increases to at least 20% if both players involved in a collision are wearing them.

There is no 100% impact-resistant headgear for NFL players

The league introduced eight position-specific helmets for quarterbacks and linemen this season. The position-specific helmets are not impact resistant, but are designed to limit head trauma.

“Anyone can get a concussion with the right hit in any helmet,” NFL chief Dr. Allen Sills to The Associated Press. “What we always look at is relative risk reduction. And wearing one of the best performing helmets certainly lowers a player’s risk of concussion. And again, that’s what our lab data and our field data have shown over the last eight years.”

The NFL says the Guardian Caps have been effective

The NFL said last week that it had seen the fewest preseason concussions since tracking began in 2015. There were 44 concussions during practices and games, a decrease of about 24% from last year. The use of the Guardian Caps was one of the reasons league director Jeff Miller cited for the reduction.

Who else uses the caps besides NFL players?

More than 300 college programs, 3,000 high schools and 750 youth programs across the country use the limits.

When were the caps made?

Guardian was founded in 2010 by Erin and Lee Hanson. The Guardian Cap was launched in 2011 and became available in 2012 after successful biomechanical and field testing.