From Lems:

It took us nearly a decade of thoughtful design and prototyping to create the Primal Zen - the successor to the beloved Primal 2! The Primal Zen offers the same minimalist casual shoe that is vegan-friendly and zero-drop, but with some added cushion and a more grounded base. Its newly designed outsole guarantees that ultra-light fit and feel you've come to love in the Primal 2, yet adds a bit more protection and durability with its platform that naturally wraps the shape of the foot. Its upper is built with a combination of breathable air mesh and microfiber, so your feet will truly feel at peace wherever your next journey takes you!