2.5mmVivos are designed with thin soles to help reconnect you with the ground, and provide flexibility for strong, healthy feet.1.5mmTread depth refers to the thickness of the patterns or "lugs," on the sole. These are purposefully designed to cater to specific surfaces and conditions, providing an ideal combination of traction, grip, and a sense of connection with the ground.The Motus Flex Outsole is designed with calisthenics experts for pinnacle barefoot-movement performance. It’s our thinnest rubber sole, decoupled (separated into two parts) for full flexibility and mobility. Perfect for primal movement, calisthenics, yoga, and more.You’re an incredible super-organism packed with raw potential. Let your body do what it does best. Embody natural movement.