Sports offer us hope, promise, excitement, disappointment and very few guarantees.

One of those guarantees? Free T-shirts!

Ever see all the fans in a section remain in their seats when T-shirts are being thrown or shot from a cannon into the stands? Nope.

The Mets are taking that a step further in 2015 with their "Free T-Shirt Fridays" promotion. All fans attending a Friday night game at Citi Field this season will receive a free T-shirt. Have a look at the designs being featured in 2015 below. (Note: Some designs may be changed or modified before game day.)

Credit: Mets

April 17 vs. Miami Marlins
"The Dark Knight of Gotham" returns for the Mets this season, so what better way to kick off Free T-Shirt Friday at Citi Field than a black T-shirt of Matt Harvey. There's a decent chance Harvey could be in line to start this game as well.

Credit: Mets

May 1 vs. Washington Nationals
The T-shirt honors the Mets' inaugural season of 1962.

Credit: Mets

May 15 vs. Milwaukee Brewers
This T-shirt design seems to be inspired by exterior designs from Shea Stadium, the team's old ballpark.

Credit: Mets

May 29 vs. Miami Marlins

Credit: Mets

June 12 vs. Atlanta Braves
Gold Glove centerfielder Juan Lagares is the subject of this T-shirt design.

Credit: Mets

June 26 vs. Cincinnati Reds
This design features Mets captain David Wright.

Credit: Mets

July 10 vs. Arizona Diamonbacks
This T-shirt features five small icons.

Credit: Mets

July 24 vs. Los Angeles Dodgers
The hair of Mets 2014 rookie of the year Jacob deGrom is silohuetted on this T-shirt design.

Credit: Mets

July 13 vs. Washington Nationals
This T-shirt features the Mets' logo written within the shape of New York State.

Credit: Mets

Aug. 14 vs. Pittsburgh Pirates
The T-shirt features Mr. Met.

Credit: Mets

Aug. 28 vs. Boston Red Sox

Credit: Mets

Sept. 18 vs. the Yankees
This orange T-shirt features the Mets logo and the city written twice, a nod to the Subway Series.

Credit: Mets

Oct. 10 vs. Washington Nationals
The design for this final free T-shirt of the 2015 season for the Mets focuses on the team's retired numbers.

Black Friday$1 FOR
1 YEAR
Unlimited Digital Access

ACT NOWCANCEL ANYTIME