GradeThread

Deep Stretch Long Sleeve Cinch Open Back

Lululemon style code W3BNNS.

Agreed across marketplace listings. Seen on one marketplace listing so far.

Style code
W3BNNS
Brand
Lululemon
Made for
Women

See a listing that confirmed it

The style code is printed inside the small circle in the pocket, waistband or neckband — the size dot. It is six characters starting with W or M, sometimes with an L in front.