Interlock Engineering
Fabric is where everything starts. Before silhouettes, before color, before branding — there’s material. And for Spring/Summer 2026, one fabric in particular has become a cornerstone of what we’re building at Rookline: interlock knit.
At first touch, interlock fabric feels deceptively simple. Soft. Substantial. But under the surface, it’s a quiet feat of engineering.
The Hudson Hoodie in Elephant and the One Under Cap in Black.
Interlock knit is a variation of rib knit construction. Unlike traditional single-knit fabrics, interlock is created by knitting two layers simultaneously on the same machine. These layers are interlocked — literally — making the fabric thicker, more stable, and more refined than standard stretch knits. While it may look like two separate layers, they can’t be pulled apart. That’s why interlock is categorized as a double-knit fabric.
One of the defining characteristics of interlock is that the front and back of the fabric are identical. You can recognize it by the clean rows of subtle “V” shapes that appear on both sides. This symmetry makes the fabric easier to work with from a production standpoint and creates a smoother, more consistent finish across the garment.
The Hudson Hoodie in Blue Sky and the One Under Cap in Light Grey.
From a wear perspective, interlock shines. The tight knit gives it a remarkably smooth surface and an elevated hand feel. It drapes naturally on the body without clinging, and thanks to its construction, it has built-in stretch without relying on excessive synthetic blends. The result is a fabric that moves with you, holds its shape, and feels intentional.
Interlock is also warm without being heavy — an ideal balance for transitional layering. It’s comfortable enough for everyday wear, polished enough to feel considered, and durable enough to hold up over time.
The Hudson Quarter-Zip in Light Grey, the Hudson 3-Button Polo in Micro-Floral White and the Malta Short in Light Grey.
We spent a long time refining this fabric because it sets the tone for what’s next. Interlock isn’t flashy. It doesn’t need to be. It’s confident in its construction and understated in its performance. Exactly how we like it.
This fabric will make its debut across several new pieces launching in early March. If you care about how something feels as much as how it looks, this is one worth paying attention to.
