The present invention attempts to replicate in footwear, orthotics, and other products the naturally effective anatomical structures like a bare foot that provide superior flexibility, cushioning, and stable support compared to existing products. More specifically, the invention relates to a device for such products including a unitary internal sipe component, said internal sipe providing increased flexibility for said device. Even more specifically, the invention relates to footwear, orthotic or other products with an outer chamber and at least one inner chamber inside the outer chamber; the outer chamber and the inner chamber being separated at least in part by an internal sipe; and the internal sipe providing increased flexibility, cushioning, and stability.