The Kansas City Chiefs are making a small change to their uniforms this week.

The Chiefs will wear gray-colored face masks to honor their 1969 Super Bowl win against the Minnesota Vikings. Kansas City’s opponent in Week 9 happens to be the Vikings. Why gray-colored face masks, though?

For many years, dating back to the pre-merger days, all NFL face masks were gray. It wasn’t until the mid-1970’s that NFL teams, including the Chiefs, began to stray from the normal gray face masks and use colored face masks. In 1974 the Chiefs switched over to the white face masks, but now to celebrate their past they’ll make a switch back to the old-school gray for a week.

Check it out:

It’s not entirely clear if this will count toward one of the three alternate uniforms the Chiefs are allowed to wear in 2019. Regardless, this is a pretty cool and easy way for the franchise to pay homage to everyone who came before them. Especially those who helped earn the team their first and only championship.

Here’s another look at the gray face masks from the Chiefs’ locker room courtesy of 810 Sports Radio’s Joshua Brisco:

The last time the Chiefs wore gray face masks appears to be Sunday, November 15 in 2009. The NFL hosted several AFL legacy games that season to celebrate the AFL’s 50th anniversary season. The game came against the Oakland Raiders and the Chiefs won 16-10. They also wore their Dallas Texans decals during that game instead of the Chiefs’ Arrowhead insignia.