Side Vents (Split Hem)

Reach overhead in a straight-hemmed polo and the whole shirt rides up with your arms; side vents — small slits, usually 1.5 to 3 inches, left unsewn at the very bottom of the side seams — are the fix mills sew in so the hem can move independently instead. On polos and fashion tees they're typically finished with a small bar tack or a folded coverstitch at the top of the opening so the vent doesn't tear further up the seam. Retail brands lean on side vents heavily; mass-blank suppliers use them less, which is part of why a retail-styled tee feels different in the hand than a bulk promotional blank even in the same weight.

Vents let the hem move independently on each side, so the shirt drapes over the hips instead of pulling tight when the wearer sits, bends, or reaches — a small thing, but exactly the kind of detail that makes a shirt read as "nice" rather than "bulk blank" the moment someone puts it on. Brand clients have asked us for vented tees specifically for a retail launch, just to get that upgraded drape without touching the print at all.

Vents don't change print placement directly, but they do mean the last couple inches near each side seam will flare slightly, so keep full-width bottom-hem graphics clear of that area or expect some distortion once the shirt is worn. Pair a vented hem with a curved hem and the flare becomes even more noticeable.

People sometimes mistake side vents for a construction flaw — an unsewn seam — and assume the garment is defective. They're intentional, not a mistake, and a shirt without them isn't lower quality, just built to a plainer, boxier spec.