What is the “third piece,” and why should you add it to your workout wardrobe, stat?

This year saw the popularization of a new silhouette in activewear: the cropped sports bra-high waisted leggings combo (AKA the twin set). It’s become a go-to look for fashion forward fit gals, whether you favor studio work, yoga, high-intensity interval training, or a combination of them all.

But with temperatures cooling, this season’s going to revolve around “the third piece,” a concept which fashion consultant Devina Foley says “is really about finishing off the look as you’re going to and from your workout. It’s not about the practical layer you wear while going for an outdoor run.”

“This is really about finishing off the look as you’re going to and from your workout—not the practical layer you wear while going for an outdoor run.”

It’s a statement maker worn to polish off the rest of your activewear ensemble, and “the options in this category have gotten so much better in the past year,” Foley says. “Instead of having to dig out an old sweatshirt or fleece or any old puffer jacket, now there are incredible styles in all different weights to layer up.”

The most classic third piece of all, also happens to be Foley’s favorite: “I love the look with a leather biker jacket,” she says. But new iterations include bombers and pullovers—plus cropped or oversized denim or field jackets in eye-catching materials like metallics or high-gloss velvet. As fall segues into winter, consider options of all of the above lined in shearling, as well as fur-trimmed parkas in unexpected colors like ox blood. The bottom line is that it should be considered an intentional extension of your outfit—not an afterthought.

Someone else who’s spotted this shift toward layering in a mindful manner is fitness blogger Melissa Eckman, AKA MelisFit, who sees it not just as a transitional piece in the seasonal sense, but also in its ability to lend a more lifestyle feel to your fitness fashion.”

“It can elevate your look in an instant.”

I’m a huge fan of the third piece because it makes it easy to go from your workout to dinner with friends, etc.,” she says. “It can elevate your look in an instant.” Her specific style of choice? “Oversized pieces work great because workout clothes are tighter, and it gives an edgy/easy feel to the look post-sweat,” she says. “I also love to get my third pieces in non-traditional colors because it makes a fun statement.”

Whatever your specific preference may be for this addition to your activewear wardrobe, it’s undeniably one of the most fun categories to shop within.

Below, are 7 on-trend third piece options Devina Foley suggests scooping up now before they fly off shelves for good.

The Third Piece

Alala Metallic Woven Fuel Jacket $210

Ultracor Silk Collegiate Bomber Jacket 250

The Upside Maison Anorak $175

Sol Angeles Madrugada Bomber Jacket $148

Alala Trix Jacket $215

SAM. Freestyle Bomber Jacket $348

Mackage Rena-d Jacket $950

Here, 16 more activewear pieces that’ll keep you warm as temps cool. Plus, 4 sweaters to pair with leggings ASAP.