At Kastel, we believe one shoe can do more. By designing modular components—like the removable shaft on Kollen—we make shoes that adapt to your needs. Add warmth and coverage when needed. Remove it when you don’t. This is just the beginning of how we’re rethinking footwear to extend use, reduce waste, and keep you comfortable through it all.

These shoes come with a size insert, designed to improve fit and reduce returns. Offering half sizes helps, but it also creates stock and production challenges. Instead, we developed a size insert that adjusts the fit by half a size, ensuring a better fit without extra production. If a shoe feels slightly off, this simple solution makes it just right.