When birddogs put a liner inside a pair of shorts back in 2015, it changed how guys dressed for the gym, weekends, and just about everything in between. One simple idea – build the underwear in. It worked. Shorts became easier, more functional, and better suited for real life, not just the gym.

Fast forward to 2026, and birddogs has done it again, this time with a lined quarter zip.

At first glance, it’s the same silhouette everyone already knows. A clean, classic quarter-zip that works anywhere you’d normally wear one. The difference is underneath. The built-in liner functions more like a dri-fit shirt than traditional insulation. It manages sweat, stays breathable, and adds warmth without feeling heavy or restrictive.

The comfort is immediate. The stretch is noticeable. It works in cool mornings, stays comfortable as temperatures rise, and moves naturally throughout the day. You put it on and don’t think about it again.

That’s the point.

They may have started as a shorts company, but the quarter zips are the real deal.

And once again, it’s hard to go back.