The Double Heavyweight Long Sleeve Tee from Wonder Looper is a true benchmark in premium t-shirts. Crafted entirely in Japan, it features an extraordinary 409 GSM (12.1 oz/yd²) jersey – making it one of the heaviest t-shirt fabrics ever made.

At nearly twice the weight and thickness of a standard heavyweight tee, this shirt delivers unmatched density, structure, and presence. Woven on vintage circular knitting machines, the fabric carries a unique slub texture, giving it a subtle irregular character and rich visual depth.

The Long Sleeve T-Shirt has a modern athletic fit with binder neck ribbed collar and a ribbed sleeve opening while the flat side seam construction, sewn on Union Special machines, recalls the refined finishing of vintage Japanese sweatshirts.

Every detail of this tee reflects Wonder Looper’s uncompromising craftsmanship and dedication to quality — resulting in a garment built to stand out and built to last.

Fit Notes: Although Wonder Looper is a Japanese brand, the sizing runs closer to Western standards. If you typically wear a size M in American t-shirts, you’ll find the same size works well here. For the most accurate fit, we always recommend checking our detailed size chart before ordering.